E39 Aux Fan Service - READ ON

[PENER]

as many of you know, auxiliary fan failure is one of many weak points on most bimmers. just to remind, it's the electric fan mounted in front of the A/C condenser (that is located in front of the radiator) that sometimes makes our cars sound like an airplane during acceleration.

the aux fan is always on (low speed) whenever A/C compressor is on, to cool off the refrigerant flowing through the condenser (using A/C without properly functioning aux fan can cause compressor failure). when it's very hot, the fan may go into medium or rarely high mode, which really sound like an airplane, to provide some extra cooling for the cooling system.

additional info: the connector for the fan consists of four wires:
brown-ground
blue-12v direct to fan, high mode
red-12v through single resistor to fan, med mode
black-12 through both resistors (in series) to fan, low mode

you can notice the first problems with the fan if it's not coming on when A/C compressor is on. the possible reasons of this are:
-bad fuses: #7,20,22 or 75, the last one being under and behind the glove box comp.
-failed resistor(s)
-failed radiator temp switch
-failed fan motor
(-rarerly failed relay)

most often it is either bad resistor pack or fan. it's worth mentioning that a failed resistor may often cause the fuses to blow. the reason for that is that with failed resitors the fan is not working on low speed and on the occasions it is kicking into high there is too much current draw.

to check whether it's the mulfunctioning resistor, (assuming all fuses are OK) you can just jump pins at the temp switch, or connect 12v DC directly to the fan connector (brown-ground, blue-12v positive). if the fan kicks in high mode, the problem is the resistor pack ($50-60).
if the fan is not working at all, the second method (direct 12v) will tell you whether the fan motor is the culprit.

most online vendors want almost $60 for the resistor packs and the fan motor alone is a whooping $200. preety steep, considering the entire fan assembly costs $300, though seeing the size of the motor and how powerfull it is, no wonder it costs so much.
below is the pic of the fan motor from one of my favorite online vendors, charging around $190 for it
http://i10.photobucket.com/albums/a139/PENER/e39fanonline.jpg

however, I have been able to spot a tremendous deal for the very same motor at Autozone. the same fan (SIEMENS PM9047) they sell for ONLY $82!!!
below it the fan motor I ordered from AutoZone
http://i10.photobucket.com/albums/a139/PENER/P1040006.jpg
as you can see, it's the very same fan, and actual replacement part for our cars. comes terminated with the prongs that slide into the connector and even has a part of the blue wire stripped in place where resistor packs connect to it

some pics of my old fan and new replacement
http://i10.photobucket.com/albums/a139/PENER/P1040007.jpg
http://i10.photobucket.com/albums/a139/PENER/P1040008.jpg

(I'd like to add here, that upon removal of the old fmotor, I found it to be still spinning with 12v put to it, although it did not work during the earlier tests. however many owners can confirm similar results with their old units. but now, knowing that you can get the new motor for only $82, it's no brainer...)


replacement of the fan resistor pack or entire fan assembly requires the bumper to be removed first together with both headlights and the (kidney) cowl. sorry for the crappy pic (low light conditions) BTW in case someone wonders where is the Secondary Air Pump (bottom left corner of the pic), it's been replaced with new type pump and retrofitted under the hood.
http://i10.photobucket.com/albums/a139/PENER/P1040011.jpg

good luck

[jbiel]

Being in Florida and using the A/C constantly, the aux fan in my 99 540i is LOUD, I am wondering if the fan *should* be that loud at all times or is it just because of the work it's doing for the heat / A/C system.

I'd like to replace it because its so loud, but if even a new one will be that loud, I won't even worry about it.

Great write up though.

[PENER]

with the engine running the fan noise is hardly noticable unless it kicks in into high. and since the noise is mostly coming from the fan blades cutting through the air, replacing the motor could only worsen the matter, as the new one would pull even stronger.

[franka]

Being in Florida and using the A/C constantly, the aux fan in my 99 540i is LOUD, I am wondering if the fan *should* be that loud at all times or is it just because of the work it's doing for the heat / A/C system.

I'd like to replace it because its so loud, but if even a new one will be that loud, I won't even worry about it.

Great write up though.

Like Pener said it's the blades cutting thru the air that makes the sound, not the motor.

The aux fan's function is to move a lot of air thru the radiator on an "as needed" basis. If it's on it is needed.

Therefore I would not recommend tampering with it to decrease the noise.

[oekundar]

Great write-up!

[jbiel]

Thanks for the responses guys, I just wanted to clear my mind of thinking I had a bad Aux Fan.

[Hotswimmer]

PENER,

Really nice write-up. Can you also post this to the E39 FAQ so it stays right up front where we can find it?

Thanks!!!

[PENER]

thanks guys.

feel free to post links to this thread.

I don't really see anything big in this thread. it's mostly summs up the issues with the fan. the real reason I post it, was to let everyone know that there is no need to spend $200 for the fan motor when there is one place (located all over the states) that sells it for $80.

[SleekBMW]

I am actually going to go buy all the parts for this, but Autozone cant seem to find it without a part number, and i gave them the part number in the fan motor above. they didnt find it.

Anyhow, where can i purchase the resistor packs? Also, to get to fuse number 75, do i have to remove the glove box or just kneel under my glove box?

what is the part # for the resistor packs?

[BlackSapphire]

My fan was noisy as hell but I didn't realize how much so until the dealer replaced it. They were trying to fix a complaint I had regarding transmission noise and they thought maybe that's what I was hearing. Once they replaced the aux fan, THEN they could hear the noise I was complaining about.

[e39dream]

great write-up! I bookmarked it for future reference. I will be posting a link to this in my cooling system thread up top, thanks Pener!

[SleekBMW]

am i supposed to buy 2 resistor packs from bav auto or one?

BTW i just purchased the fan motor, and i want everyone to know
that at autozone, that is listed as Radiator Fan motor with part # PM9047, make sure they put PM or spark plugs will come up, i had to travel to 3 autozones before they figured that out, i carried my laptop showing them until i found a younger dude in his 20's hes like, ok here you go in like 1 min. so FYI make sure they put in PM9047

[SleekBMW]

Quick question, what is a pick that is needed to remove the bumper?

[e39dream]

I know theres a special puller tool for the plastic push in rivets but I don't think it's needed for a one time removal/install provided you buy a hand full of new rivets to put it back together with. They are the things under the bumper trim with the centers that pull out, making the fastener smaller in diameter and easier to pull out. It's simple enough to pull the center pins with needle nose pliers and pop the fasteners with a flat screwdriver or small scraper.

[e39dream]

it's either part 22 or 31 on this diagram, get 10 of each to be safe lol.
the parts counter at BMW dealerships have these on hand.

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=51_2253&hg=51&fg=15

[NY550i]

Can the motor be making noise or just the blades?
Im actually having issues with my aux fan... it is way to loud! once the car warms up to normal temperature the aux fan goes on and the car idles with a loud fan

I took the car to a indy and they replaced the whole aux fan with a new one and it still made noise so they said the fan might be defective so they will replace it with another new unit... im starting to believe the problem is not in the fan but something else

[Dan]

PENER,

Really nice write-up. Can you also post this to the E39 FAQ so it stays right up front where we can find it?

Thanks!!!
+1

greg, replicate his up there! :)

[SleekBMW]

it's either part 22 or 31 on this diagram, get 10 of each to be safe lol.
the parts counter at BMW dealerships have these on hand.

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=51_2253&hg=51&fg=15

lol, i have a tendency to mess up...im going to get 20. of each:shifty




I know theres a special puller tool for the plastic push in rivets but I don't think it's needed for a one time removal/install provided you buy a hand full of new rivets to put it back together with. They are the things under the bumper trim with the centers that pull out, making the fastener smaller in diameter and easier to pull out. It's simple enough to pull the center pins with needle nose pliers and pop the fasteners with a flat screwdriver or small scraper.
So far this is what i understand, and i appreciate you letting me know that you will help me do this, but i have to do this urgently as i have to drive down to St. Louis this friday.

so i will take pics and make a DIY but this is what i understand so far please correct me if im wrong
tools needed - I have a regular 3/8 drive wrench with a 1/4 adapter
8mm socket
13mm socket
10mm socket
T45 Torx from Murrays @ 6 dollars came with 40-45-50.
needle nose pliers
5-4' extensions (just in case)
a pack of cigarettes. (may come in handy if im frustrated)

1- disconnect battery
2- remove the screws that connect the bumper each side of the wheel well
3- remove screws at the fog light grill
4- go under the bumper and use the needle nose pliers and PULL those picks out as hard as i can.
5- after fog lights etc have been removed pull the foglight grill out
6- find the place where the T45 torx and unscrew that piece
7- pull bumper off
8- remove they kidney shroud
9- remove the auxilary fan shroud
10- loosen away fan motor
11- clean fan and condensor etc
12- screw in new motor
13- unplug old resistor pack and plug in new one
14- follow steps and put the whole thing back together again.

Now i will have a function auxilary fan

But i have a question, what the hell is that thing that is circled in red? and howdo i get it off?
http://i7.photobucket.com/albums/y255/Shazeb/12.jpg
http://i7.photobucket.com/albums/y255/Shazeb/11.jpg

pics courtesy of BMWtips.com

thanks for all your help, i will make a DIY for this with LOTS of pics.

[SleekBMW]

bump

[e39dream]

hey sleek thats the air inlet to the air filter- it snakes into and behind the bumper support- yours will be a little different than pictured because its a 6 cylinder. As for how it comes off- you may have to pioneer a little :) That whole snake looking thing is in the extra parts pile of my car :shifty

[SleekBMW]

thanks man! i appreciate it, lets see how this goes!

[SleekBMW]

Just in case Greg didnt get my Email,
How do you remove the fan from the motor?
how do you wire the new wires into it powering the fan?
The motor ONLY came with 2 wires.


Anything else i will post
Thank you ALL for your help..Actually for this i thank Mark and Greg.:D

[SleekBMW]

bump

[NNY528I]

Any one know off the top which wire in the resistor pack goes to which pin in the connector. I was hopped up on coffee after a late night run and failed to note there positions when i pulled them out. The 2 in question are the black and the black and red.

Thanks,

[md80boy]

what is the number of the packs and where can we buy them?

[jamesdc4]

Great thread. Thx for the info!

[jase007]

Just ordered my motor from autozone online. We'll see what it looks like when it arrives. My peake tool is throwing a 7d code which translates to auxillary cooling fan final stage. All fuses check out OK. replaced temp sensor in lower radiator hose already so ... will R&R the motor.

Also ordered #67328371873 per realoem.com for my wagon which is the AC and Heat - Condensor fan - resistor. Realoem.com lists it as a "repair kit resistor".

Thanks for the tip. :)

[runnerboy]

i can't seem to find just the aux fan motor anywhere. any tips? direct links??

[PENER]

I'm rarely on bf.com nowadays, but seeing this old thread reactivated I'd like to add: please read the posts carefully and I'm sure you guys can figure it all out by yourself


Any one know off the top which wire in the resistor pack goes to which pin in the connector. I was hopped up on coffee after a late night run and failed to note there positions when i pulled them out. The 2 in question are the black and the black and red.Thanks,


additional info: the connector for the fan consists of four wires:
brown-ground
blue-12v direct to fan, high mode
red-12v through single resistor to fan, med mode
black-12 through both resistors (in series) to fan, low mode



As far as the resistors, both are exactly the same. which one hooks up where is clearly stated in my original post (see quote above). brown wire is ground to the motor. blue is direct 12v to the motor. red goes from the harness through the single resistor and connects to the blue (that's what the stripped part of the blue wire is for) wire. black also goes from the harness through other resistor, then connects to the red wire (before the first resistor on the red wire!!!). in other words...

Brw..Blu...Red...Blk ................R-resistor..............edit: dots (....) mean nothing, w/o them the pic would get messed up
|.....|......|......|
|.....|......|......R
|.....|......|......|
|.....|......|..... /
|.....|......R..../
|.....|......|../
|.....|......|/
|.....|....../
|.....|..../
|.....|../
|.....|/
|.....|
\.../
fan

of course the resistors are wired all close to the fan so they can be exposed to the air flow. after all, being the resistors, they can get really hot!

[jfboy]

additional info: the connector for the fan consists of four wires:
brown-ground
blue-12v direct to fan, high mode
red-12v through single resistor to fan, med mode
black-12 through both resistors (in series) to fan, low mode





I am confused...

My fan only has 3 wires
1 small balck wire
1 big red wire
1 big blue wire

I connected both big wires to a battery and the fan will not turn on? :help
:help

BTW: BAD NEWS GUYZ

Autozone doesnt carry that item anymore. I just went to them and they pulled it up on the computer and it show you can buy it anymore. :(

[Jackcat559]

Just pulled this assy off during this week. Wow, it's heavy for a fan.

[Jackcat559]

Can we put this in the DIY section? It was extremely handy this weekend.

[Gumbi4u]

Can we put this in the DIY section? It was extremely handy this weekend.

Done :buttrock

[Jackcat559]

Thanks Gumbi :thumbup:

[Jackcat559]

Here are some pics from this weekend. I beleive the motor is bad. The contacts had a minor amount of corrosion that was cleared up with a little contact cleaner.

The fan has 14V DC suppied.
Brown looks to be ground, and the other two must be high & low.
http://i40.photobucket.com/albums/e235/Jackcat559/113-1303_IMG.jpg

The motor only registered in kilo-ohms.
http://i40.photobucket.com/albums/e235/Jackcat559/113-1304_IMG.jpg

In going to check out the local supply companies to see if the motor is available.

[Aero Guy]

I couldn't find the motor at the local parts houses but found a cross reference to a Four Seasons model. Ordered from below and the Siemens motor showed up with the right pins on it and the hook up for the resistors. A plug and play replacement for much less than the complete assembly shown by most online places!

I'm not allowed to post links yet but search for FS75720 at autopartswarehouse.com It's listed for a '97 740 but is the same as mine '97 528

[Chachi15]

where is the radiator temp switch located? I would like to test the motor to see if its not the cause for it not operating

[Vipsa]

Can anyone confirm that this motor will work on 98+ cars? According to Siemens this is only for 96 and 97 MY E39s.They also don't list anything for the later years. Autozone doesn't carry this anymore, but apparently Pepboys does with special order.

[Chief2011]

My A/C wasnt blowing correctly on my recent 2003 525i. I checked the aux fan and it was at a stand still. I turned the blades slightly and it started after a few seconds and the a/c started again- but not great. What is the issue:fan motor, resistor, or something else?

Thanks John

[BimmerGoon]

whats the difficulty on this? I'm a beginner and I think this will need done soon to my car, BUT if its difficult then I may just go to a shop. Any ideas on how much this would cost at a shop?

[Smookey525i]

Can the motor be making noise or just the blades?
Im actually having issues with my aux fan... it is way to loud! once the car warms up to normal temperature the aux fan goes on and the car idles with a loud fan

I took the car to a indy and they replaced the whole aux fan with a new one and it still made noise so they said the fan might be defective so they will replace it with another new unit... im starting to believe the problem is not in the fan but something else

I had this same issue about a month ago... I took my bimmer to the autobahn shop in Laurel... The mechanic told me that it was the aux fan and it would cost 680.00 :nono not me I went down to brandywine a local junkyard (lifetime warranty on all parts) and picked up a fan for 250.00 and installed myself. GUESS WHAT!!!!!! the new/used aux fan is still LOUD :shifty.... Then the little light bulb came on. Let me check the coolant temp. sensor 23.00 at bavauto.com (sits on the lower radiator hose) and VIOLA!!!!! :alright Even though I really didnt need to change the aux fan (which couldve save me 250.00 beer money) I still feel as tho I made out vs the 680.) Lesson learned, start from sensor then work your way to the actual part you will save more money using that strategy. :buttrock


whats the difficulty on this? I'm a beginner and I think this will need done soon to my car, BUT if its difficult then I may just go to a shop. Any ideas on how much this would cost at a shop?


It took me a couple of hours because it was my first time... but all you have to do is get the dang bumper off and drop the aux fan and you should be good to go......but before you do that (as I have mentioned before) check your coolant temp. sensor

[Jackcat559]

Damn what made him think it was the fan? A basic electrical test would have let him know weather it was working or not

[Smookey525i]

Damn what made him think it was the fan? A basic electrical test would have let him know weather it was working or not


Welllllll the problem was in my case that the b*tch would not shut off and made a god forsaken LOUD noise constantly from the moment the car got a little warm till I shut it down (in this case it sounded like I was shutting an aircraft down). So he figure it was the modulator which controls the speed and if it should be on and off..... If I'm correct the modulator that sits in the back of the fan recieves information from the coolant temp sensor...Sooooooooo if the sensor is jacked up then guess what.... The frickin aux fan will keep on going thinking that it needs to be on *based off the info from the coolant temp sensor.

[Jackcat559]

gotcha

[Xenocide]

seems as though this fan motor is no longer in production, the part that has replaced it (manf. by four seasons) is $180. I may just go ahead and get whole shroud assembly from dealer, ugh.

[turbo20psi]

Parts bin has it for 184.74 and a 1 year warranty.http://www.thepartsbin.com/catalog/?N=1580+9735+4294963367+4294952362

[Xenocide]

Just got the depo fan in from ebay, its not OEM quality but will work fine.

[kaane21]

Can anyone here help me out. I hav a 01 540i, aux fan less than a year old... My fan seems to operate only on hi mode, as a result my temp goes up constantly to near danger levels... Any one that give a little insight greatly apreciated

[Mulepick]

Here in Vegas I've had plenty of occasions to heard the aux fan on high. I thought it was bad because it was so loud but now that I see what it looks like, it's no wonder it's loud.

[528itwagon]

Just an FYI for those of you in need of a new fan. Mine exploded and forced me to buy an entire assembly. I called a friend at LKQ which is a nationwide salvage yard. He sold me an entire aftermarket assembly for 150 bucks. Bolted right in and plugged in!!!!!! All new and works perfectly.

On a side note those of you removing the bumper for the first time. I would highly recommend just leaving the bumper cover attached to the bumper and simply removing the fog light covers, 4 bolts attaching the air ducts, inner fender bolts, and the bumper shock mounting bolts (6 big ones, 4 small ones). It all comes off together and you don't have to worry about breaking all the bumper cover clips. Just my opinion.

[simont540]

if anyone needs the resistor repair kit, I found this surplus place in NC blowing them out for $31.20 (or you can buy 200 of them for $4300 :)
Shipped mine same day ! half the price of the best I could find !

http://hedrick2.com/main/index.php?page=shop.browse&option=com_virtuemart&Itemid=40&lang=en

Just type in BMW in the search field

[E39 Wagon]

ok, so i have a 99 540iT sport with a aux fan that isn't turning on when the a/c comes on rendering my a/c useless. i have gone through this thread and the other one and still have some questions. i have a plug with 3 wires going to it that has power ground and trigger. with the car on and a/c on i have ground on the brown wire, power on the blue wire and power on the remaining small wire. so i can assume my fuses are good, mainly the 75 amp on under the glove box. so i bought a new fan assembly and plugged it in without pulling my whole front end off and it didn't come on. so i started the car and it came on. so i was like ok, cool, progress. to further substantiate this i unplugged the new one and plugged in the old one and it turned on for about 30 seconds and stopped. so now i am thinking its the temp switch. so i replaced that and still nothing no fan. one question i have is that i was seeing a ground at the switch instead of power like the wire at the plug by the aux fan, is that correct? also i have the fan that has the box on it which i assume its the resistors.

someone please help, its been 2 weeks now without a/c and the florida heat is killing me along with all the smoke from the wild fires.

[CSMBlack-540i]

also i have the fan that has the box on it which i assume its the resistors.



The troubleshooting of the Aux fan really depends on whether you have the one with the resistors or the one controlled by the ECU. You need to determine first whether you car SHOULD have the old style or new style. It is particularly important for you since you are at the cusp 9/98 when they changed over at 8/98.

If you bought the old and try to connect to the new, I don't think it will work.

[E39 Wagon]

i have this thread where we have made good progress but aren't quite there yet. http://forums.bimmerforums.com/forum/showthread.php?t=1671166

we have concluded that i have the newer 3 wire fan, which is the one i bought as a replacement, so i am good there, just need to figure out how to trouble shoot so i can be sure its the fan before i spend the time taking the front end of my car off.

[CSMBlack-540i]

i have this thread where we have made good progress but aren't quite there yet. http://forums.bimmerforums.com/forum/showthread.php?t=1671166



Yeah, I know. I posted in reply #8 and #11 there.

[DownyFresh]

Can anyone here help me out. I hav a 01 540i, aux fan less than a year old... My fan seems to operate only on hi mode, as a result my temp goes up constantly to near danger levels... Any one that give a little insight greatly apreciated

Mines is doing the same thing i got a 98 528i when i put the ac on it takes about 10 to 12 minutes for the fan to kick in and by that time its too late the TEMP is already rising.

[macgy]

I hv d same problem with my 99 523i, d fan will move a bit but it doesn't continue, I replaced it with a new fan & it has been fine since

[DownyFresh]

Yeah, I know. I posted in reply #8 and #11 there.

I have the same problem i got a 98 528i production date 6/98 , when i put the ac on the ac is cold but the fan doesnt come on right away it takes about 10 to12 minutes to come on and then the car starts to overheat when i turn the ac off it doesnt overheat anymore the temperature goes back to normal, and then when i check the power outlet for the ac with the car on and the ac on , 1 wire is the ground and only 1 wire has power so theres 2 wires left but they have no power, should all 3 wires have power? Plus 1 be ground? Somebody please help

[joako]

I have the same problem i got a 98 528i production date 6/98 , when i put the ac on the ac is cold but the fan doesnt come on right away it takes about 10 to12 minutes to come on and then the car starts to overheat when i turn the ac off it doesnt overheat anymore the temperature goes back to normal, and then when i check the power outlet for the ac with the car on and the ac on , 1 wire is the ground and only 1 wire has power so theres 2 wires left but they have no power, should all 3 wires have power? Plus 1 be ground? Somebody please help

Sounds like the resistors are bad.

[DownyFresh]

Mines is doing the same thing i got a 98 528i when i put the ac on it takes about 10 to 12 minutes for the fan to kick in and by that time its too late the TEMP is already rising.

If u see ur temp goin UP turn ur AC off immediately and if its still goin up turn the car off so u dont damage ur engine,its either ur fan is bad or ur resistors if ur fan got those,like i said mine is doin the same thing i think its the resistors im gonna try to change them this week ill let u know how it went.

[joako]

If u see ur temp goin UP turn ur AC off immediately and if its still goin up turn the car off so u dont damage ur engine,its either ur fan is bad or ur resistors if ur fan got those,like i said mine is doin the same thing i think its the resistors im gonna try to change them this week ill let u know how it went.

Turn off the A/C and keep on moving at least 20mph.

If the ONLY issue is the fan, it will never overheat while moving.

[DownyFresh]

Turn off the A/C and keep on moving at least 20mph.

If the ONLY issue is the fan, it will never overheat while moving.

Yeah thats what i do as soon i turn the AC off and keep the car moving the needles goes back to normal.

[Petes540i6]

I am so subscribed to this thread.

[joako]

Yay! So I spent all day today taking off the bumper, cleaning all the little hard to get to places, install the 2nd replacement fan, make sure all the screws were correct & tight. No more rattling/thumping noise when the fan operates!

Thanks to PelicanParts.com for cross-shipping a replacement fan.

Watch out with the condenser! Pressure washer too close will mess it up!!

[chrisesteschiro]

I bought the resister kit but ended up not needing it (My car is newer and didn't use it at all). It is brand new. I can send pics upon request. Make an offer :)
Part number 67328371873

[crazyb0064]

I bought the resister kit but ended up not needing it (My car is newer and didn't use it at all). It is brand new. I can send pics upon request. Make an offer :)
Part number 67328371873

interested, but cant pm yet. shoot me a msg and we can talk

[joako]

So I've gotten two fans from PelicanParts, BEHR brand. Each fan makes a chattering noise. If I jiggle the front end it stops sometimes.

Any advise how to stop the noise?

[Anthony1406]

So I've gotten two fans from PelicanParts, BEHR brand. Each fan makes a chattering noise. If I jiggle the front end it stops sometimes.

Any advise how to stop the noise?


I had the same thing and turned out my grill kidneys plastic back was touching the fan and pushing the protective shield in

[Johnny Kim]

Don't mean to bring a dead thread back to life, but was anyone able to find a cheap replacement motor after the discontinued SIEMENS PM9047?

[hawklow32]

hi i have 1997 bmw 540i when i take off resisvior cap pressure comes out from the car being cold thats wired what should i do about it.:shifty

[joako]

hi i have 1997 bmw 540i when i take off resisvior cap pressure comes out from the car being cold thats wired what should i do about it.:shifty

Change the head gaskets and see if that clears it up.

[hawkck1]

Have to ask......can you remove the cross brace at the top (After removing headlights), remove the 4 bolts that secure the fan assembly and pull it out through the top (after disconnecting electrical)?

[kchouston]

I replaced my auxiliary fan but now my AC only blows cold while I am in motion.Once I come to a stop, it stops blowing cold air,

[siny528i]

Excellent write-up!
Thanks for trying to save me some $$$ and time!

My motor is very loud.
Does it mean that its going to die soon?
Should I go to Autozone now and get replacement?

Thanks again,
siny528i

[300kplus]

Replacing the whole aux fan assembly tomorrow on my 98 e39. I'll let you know how it goes. The housing was shot couldn't save it. I think it may be original so pretty lucky it lasted this long 320k (+) And if it wasn't, I got the car when it had 295k in May of 09 so...
Will follow up.

[siny528i]

Replacing the whole aux fan assembly tomorrow on my 98 e39. I'll let you know how it goes. The housing was shot couldn't save it. I think it may be original so pretty lucky it lasted this long 320k (+) And if it wasn't, I got the car when it had 295k in May of 09 so...
Will follow up.320k? Wow! :eek:
Good luck with your repair!

[PhillH]

Just my 2 cents, I wouldn't put a new motor in with an old fan, my motor runs fine but
after so many heating cooling cycles the plastic fan became brittle and exploded. I ordered a complete assembly on Amazon for $140 shipped, I'll be attempting to put in in today, wish me luck.

[keitho64]

I have been following this thread for some time. My aux fan will randomly come on sometimes when the engine is cold and just started. There seems to be no reason. I am assuming it is a sensor and not the fan but there are no check engine lights triggered. Most of the time when it happens I don't worry since it really isn't hurting anything.

Well the last two nights I start up the car after sitting all day at work and the fan fires up and runs at full speed for at least 10 minutes. I have the HVAC control off and it is 0 outside. So now the car will take a little longer to warm up.

My brilliant fix is to find the relay for the aux fan and pull it out. The in spring trace all the feeds into the fan to see if it is a sensor or the actual fan. I really think mine is sensor related since it is so random.

Thanks for the excellent thread and I will report back in spring when it is warm enough to actually work on the car.

[wareagleash]

Someone from my office just came in and told me my car was making noise. Well I walked out and my aux fan was running full tilt and car not on?? I pulled the battery cable till I could come in a research. I've not had a lot time since I'm at work, but has anyone ever had this happen?

its 2000 528 with 152k

[trainwreck85]

Can anyone tell me the values of the resistors? I only found one at .2 ohm 80w. Are both of them the same? Thanks

[OnTheFence]

I parked last night and got out of my car.
I heard this loud whirring from the front of the car.
I thought it might be a neighbor's air conditioning.

I walk to the front of the car, and it was this loud fan whirring inside my front grille.
This is the first time in 2 years I've owned the car where I noticed an electric fan was still running after I exited the car.
Again, this has never happened before. Normally, when I turn off the car, everything is OFF.
It was only 80 degrees out, and the car was not overheating.

I thought maybe something shorted and it would drain the battery.
I came back outside 30 mins later, and luckily it was off.
Today, when I parked, the car was silent, like usual.

So, which is the proper behavior?
The fan never staying on after you park,
or the fan always still running after you park?

How do I fix this?
It seems like most people's problem is the fan stops turning on.
Mine may be the opposite.

[dannydoo]

So many good questions asked on this thread.I resurected it to compile them.
1) on 97/98 with resistor packs,should the fan go on as soon as a/c is turned on?
2)does the 97/98 do the 20second low speed aux fan test on start up.OR is that only 99 and up?It makes sense it being 99 n up,cuase the computer is testing it.
3) what are the values of the resistors? I found this one, its 0.20 OHM 80watts
4)Is there any shortcut to removing this fan?
5) What is the normal action of the fan,when car is off,and why?
6) Is it normal for the Fan speed and/or A/C to slow down or not work while you stop at a light,then blow fast again as you drive and colder again as you drive?Windshield wipers do this,so my assumption is that it is normal?
7) Is it possible to just remove the bumper cover as someone earlier posted MINI instructions?

[E39E46E36]

Bump.

My aux fan is running intermittently w/ the AC on. It attempts to spin at different intervals, but only makes jerky movements before coming to a stop. I've checked the fuses and they look OK (and since the fan is moving, I guess I could eliminate the fuse being the culprit).

My A/C only gets cold when the car's in motion. Ice cold actually. I've checked the freon levels and it's good.

Based on everything I've read in this thread, it looks like it could be the resistor or the motor. Anyone know a place where we can pick up the motor for a decent price? That $82 motor from Autozone is no longer available.

- - - Updated - - -

Also - if the temp sensor goes bad, does it throw a CEL code? I want to make sure it's not the temp sensor before purchasing the motor and resistor repair kit.

[dannydoo]

theres 3 temp sensors. the one you can check ez is on the side of the radiator. its the one that powers the fan.
your case is a dead motor!!
to be positive put 12v to the blue/blue striped thick wire and ground the brown/on the male pin side.That bypasses the resistors to high speed.
the harness is 4 pin tucked to the left of the plastic kidney shapw grill in front of fan.
AMAZON you can get a tiy 30365 fan assembly under 200,they are made as well if not better than oem. imo

[E39E46E36]

I replaced the entire fan assembly and it now works like a charm.

Side note: I have the 2001 525iT and did not see any resistors on the new or old assembly. I guess it varies depending on which MY you have.

[Yonkers320is]

theres 3 temp sensors. the one you can check ez is on the side of the radiator. its the one that powers the fan.
your case is a dead motor!!
to be positive put 12v to the blue/blue striped thick wire and ground the brown/on the male pin side.That bypasses the resistors to high speed.
the harness is 4 pin tucked to the left of the plastic kidney shapw grill in front of fan.
AMAZON you can get a tiy 30365 fan assembly under 200,they are made as well if not better than oem. imo

do you have a link? searching amazon and can't find nothing. only this: http://www.amazon.com/TYC-611240-Replacement-Condenser-Assembly/dp/B0041TJP3Y/ref=pd_sim_sbs_auto_1?ie=UTF8&refRID=1RW56R8Z6WD49H2JGNG3

[greggo151]

2001 525iT The Auxiliary fan is running at low speed, but the high speed is not coming on. Fuse 75 is good. I can't locate a fan relay. The ebox under the air intake only has 2 relays, salmon and brown, where some diagrams show more in that area. Do I have a relay? Do I move to checking the temp sensor in the radiator hose?

[99gsx]

2001 525iT The Auxiliary fan is running at low speed, but the high speed is not coming on. Fuse 75 is good. I can't locate a fan relay. The ebox under the air intake only has 2 relays, salmon and brown, where some diagrams show more in that area. Do I have a relay? Do I move to checking the temp sensor in the radiator hose?


If your E39 was made after 9/1998, you do NOT have resistors. It could be a faulty temp sensor, or you may have to replace then entire aux fan unit. I am going through this process now. I am purchasing a temp sensor first to see if that fixes the issue before i drop $300 on a new aux fan unit. After spirited driving my aux fan was not moving at all. I will post again once i switch sensors out.

[GoBucs]

I have 98 528i (04/98)
My aux fan does not turn on at start up nor when the a/c is on. My ac only blows cold when the car is moving. The fan only comes on at it’s highest speed when at a stand still if the engines starts to warm up. Do I need to replace the entire auxiliary fan?

[keitho64]

Have you replaced the sensor in the lower radiator hose? This was the cause of all my aux fan problems. It is a very easy swap and I did it without removing any antifreeze, just be quick with the swap.



I have 98 528i (04/98)
My aux fan does not turn on at start up nor when the a/c is on. My ac only blows cold when the car is moving. The fan only comes on at it’s highest speed when at a stand still if the engines starts to warm up. Do I need to replace the entire auxiliary fan?

[Tutti57]

FYI: if you have a three wire fan, you cannot just replace the fan. The cheaper replacements are only two wires and use resistors instead of the computer.

I replaced my fan and it seems to come on too easily and get to high quickly. I'm going to try that lower sensor now.

[GoBucs]

Have you replaced the sensor in the lower radiator hose? This was the cause of all my aux fan problems. It is a very easy swap and I did it without removing any antifreeze, just be quick with the swap.
Were you having the same issue as me? And is this the part?
http://www.turnermotorsport.com/p-21...0il-95-98.aspx (http://www.turnermotorsport.com/p-2170-radiator-fan-switch-e39-528i-540i-97-98-e38-740i-740il-95-98.aspx)

- - - Updated - - -


FYI: if you have a three wire fan, you cannot just replace the fan. The cheaper replacements are only two wires and use resistors instead of the computer.

I replaced my fan and it seems to come on too easily and get to high quickly. I'm going to try that lower sensor now.
Was this the fix? http://www.ecstuning.com/BMW-E39-528i-M52_2.8L/ES2185408/

[Tutti57]

My problem was that the fan blades exploded and took a lot of the surround with them, so I just took the motor out of that one and swapped the blades and surround with one I got from rockauto. I'll probably sell the teo two wire motor it came withsince I have no use for it.

My next step was that one if this didn't work.

What is the part number for that temp sensor and was there a bin split that stopped using them? I'm seeing several locations on the sites.

[keitho64]

This is the part. http://www.bavauto.com/shop.asp


Not sure link worked here is the part number. 13 62 1 433 077 Just search on that at BAV. This was for a 530 and I believe you are working on a 540 so double check the number.

My problem was the fan would come on Even when cold. It was an intermittent issue but since the fan worked I did not feel the fan was the issue which is why I went with the sensor route.

[nikatkimber]

ETA: The following applies ONLY to early model cars that are NOT computer controlled Aux fans.


Have you replaced the sensor in the lower radiator hose? This was the cause of all my aux fan problems. It is a very easy swap and I did it without removing any antifreeze, just be quick with the swap.

I'm pretty sure that the AC being turned on bypasses the aux temp sensor in the radiator hose. So if the fan doesn't come on when the AC is switched on, then the sensor *may* not be bad.


I have 98 528i (04/98)
My aux fan does not turn on at start up nor when the a/c is on. My ac only blows cold when the car is moving. The fan only comes on at it’s highest speed when at a stand still if the engines starts to warm up. Do I need to replace the entire auxiliary fan?

If the fan comes on at all, then you can likely rule out the fan motor. If the motor is bad it will either run or not for the most part (it is possible if it is going out that it will run randomly - but if you can recreate the situations that make it run that isn't likely the case). Most likely the resistor pack that drives the fan at different speeds.

[keitho64]

In my case the fan did not come on when I turned on the AC. The fan would just run when it felt like it. In one example it was below 10 outside and I just started the car but the fan was in full song.

[nikatkimber]

In my case the fan did not come on when I turned on the AC. The fan would just run when it felt like it. In one example it was below 10 outside and I just started the car but the fan was in full song.

Disregard my previous post at this point. I was reading the initial post and didn't realize that it only applies to the early models that aren't ECM controlled.

Both my car, and yours, are controlled by the computer. So the AC switch and the Aux Temp sensor send signals to the computer, and then it sends the signal to the fan.

[Tutti57]

Where is the aux temp sensor located? Radiator or water pump?

[nikatkimber]

Where is the aux temp sensor located? Radiator or water pump?

On a M62TU engine, it's mounted just behind the radiator into the lower radiator hose.

[Tutti57]

On a M62TU engine, it's mounted just behind the radiator into the lower radiator hose.
Ok thanks. Are all of those sensors the same part numbers?

[nikatkimber]

All of which sensors? I know the aux temp sensor is different than the temp sensor that screws into the pump. I know the M62TU, and I think all TU motors, don't have a temp sensor directly attached to the radiator.

[Tutti57]

Ok. I replaced the one in the hose but my car is broken so I haven't had a chance to test it out yet. Simple install.

[siny528i]

Its 47F outside now. I started her up. Turned A/C on. AUX Fan is NOT engaging.
Does it mean I have a problem?

[cnn]

Its 47F outside now. I started her up. Turned A/C on. AUX Fan is NOT engaging.
Does it mean I have a problem?

Get a straw or chopstick and try to spin the fan. It may be seized.
1997-1998 528i uses SIEMENS PM9047 = "Four Seasons 72750".

There is one on ebay for $100.

[siny528i]

Get a straw or chopstick and try to spin the fan. It may be seized.
1997-1998 528i uses SIEMENS PM9047 = "Four Seasons 72750".

There is one on ebay for $100.Thanks cnn,

Yep, I did it. Its spinning freely.

[siny528i]

Again, excellent write up!

In my case, as long as I remember, AUX fan was operating only on HIGH. Either HIGH and LOUD or nothing.
So that probably was cause by one or both faulty resistors?

Now my AUX fan is not coming on at all.

Removing bumper is not an issue.I did it already couple times.
I just wanna know if its possible to jump the motor without removing anything?

Thanks again,
siny528i

[siny528i]

Hey guys!

My fuses are Ok!

I also jumped the AUX fan and it was spinning on HIGH:
http://cyberforma.com/auto/diy/bmw/528i/1998/hvac/condenser/900x500/001.jpg

http://cyberforma.com/auto/diy/bmw/528i/1998/hvac/condenser/900x500/002.jpg

http://cyberforma.com/auto/diy/bmw/528i/1998/hvac/condenser/900x500/003.jpg

http://cyberforma.com/auto/diy/bmw/528i/1998/hvac/condenser/900x500/004.jpg

http://cyberforma.com/auto/diy/bmw/528i/1998/hvac/condenser/900x500/005.jpg

Does it point me to BAD Resistors?

BTW, those Resistors aren't cheap. In average they go for about $175. Far from what RealOEM shows.
I found one at ECSTunning for $32.90 made by MTC. Sounds like a steal.

What do you think?

TIA
siny528i

[siny528i]

Get a straw or chopstick and try to spin the fan. It may be seized.
1997-1998 528i uses SIEMENS PM9047 = "Four Seasons 72750".

There is one on ebay for $100.Yesterday I took it out and it didn't look good:
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/004.jpg

http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/005.jpg

So I decided to go with complete BEHR A/C Condenser Fan Assembly (P/N 64548380780) from AutohausAZ for $163.10 shipped.

I also found out that my condenser is worn:
http://cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/007.jpg

http://cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/008.jpg

Do you think I can have it for a while?

[Yonkers320is]

Does the a/c holds charge? If it does, why change it, we arein winter right now

[siny528i]

Does the a/c holds charge? If it does, why change it, we arein winter right now
Thanks Yonkers320is,
Happy New Year all!!!

I thought since I am already there AND I found one made by NISSENS for $139.I currently have NISSENS Radiator for the last 80k and have no complaints...

Also, how hard it is to replace it?

siny528i

[Yonkers320is]

Shouldn't be too hard, since you will be removing the bumper and all the stuff to replace the fan. You will need to unbolt the refrigerant lines. What i am not sure is if it comes out thru the front (easy) or thru the back ( remove rediator, engine fan, etc)

And Happy New Years to you also!!!

[siny528i]

Hey guys,
Happy New Year!

I just installed complete BEHR A/C Condenser Fan Assembly, BUT it shows no signs of life.
All fuses are fine. Where else I should look for?


TIA
siny528i

[cnn]

Apply fresh 12V to the Aux Fan and see what happens.

[nikatkimber]

Apply fresh 12V to the Aux Fan and see what happens.

Be careful if you do this! On TU cars, (99+) this fan is controlled by the computer, and 12v directly to the fan on the wrong pin could fry the fan's internal board.

[siny528i]

Hello guys,

Here's what I ve learned (thanks edjack from UnofficialBMW and Jim Cash from RoadFly) with some of my editing:

Double Temperature Switch 91/104CEL (located on Radiator) activates the AUX Fan when coolant reaches above average temperatures:
91C - Low speed
104C - High Speed

AUX Fan operates on 3 modes: LOW, MEDIUM and HIGH.
NOTE: Newer E39's may have a variable speed fan and these tips may not be exactly what you're looking for.
These tips are accurate for troubleshooting a 1998 540iA with a Nov 97 build date.

AUX Fan comes on at LOW mode/speed whenever the AC is ON by an input from the AC controller and the engine computer combined AND the outdoor temp is above 10C - as shown on the display in the instrument cluster AND it supposed to stay on ALL THE TIME.

Two days ago in order to check my newly installed AUX Fan I:

- Disconnected the 3 wire harness that goes to the Double Temperature Switch 91/104CEL (located on Radiator):
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/021.jpg

- Started the car;
- Using small paper clip...
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/022.jpg

...I connected BROWN wire to the BLACK wire with RED Stripe - AUX Fan started to spin at MEDIUM speed;
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/023.jpg


- Then I connected the BROWN wire to the BLACK wire with the WHITE Stripe - AUX Fan started to spin at HIGH speed;
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/024.jpg

- Shut the car down and reconnected the harness to the switch.

By jumpering at that point you are operating the relays that provide the power source to the fan.
Relays are in the E box (under the passenger side microfilter).

So my AUX Fan is Ok, but I wish I knew this trick and used it on my OLD one...

IF the Aux fan did NOT run at any speed, then I would first suspect that a fuse is blown.
IF you've checked the fuses then motor may have failed.

IF the AUX Fan only worked on the highest speed, then I would suspect that one or both of the resistors or relays that control the lower speeds have failed (no resistors are used for the highest speed, but a relay is).The resistors that control the lower speeds are located on the AUX Fan Assembly.

IF you are experiencing overheating and the fan worked flawlessly, maybe the temp sensor (the one that you disconnected to jump wires at) has failed.

PS. Yesterday morning it was moderate outside. About 52F. I started the car and my AUX Fan went ON at LOW speed.
I saw its spinning like this first time since I bought my car in 2007. Or maybe I've never noticed...

[thesniffingratt]

I have overheating issues, the aux fan does not turn on with AC, but does run only on high when jumped at temp switch (on radiator) connector. I replaced the temp sensor switch on radiator, did not help. My friend says I should replace the relays and resistors. Are these the right parts:

resistsors:
http://www.ebay.com/itm/NEW-Auxiliary-Fan-Resistor-MTC-67-32-8-371-873-BMW-E38-E39-740i-740iL-750iL-525i-/141957084674?hash=item210d4d3602:g:cFkAAOSwZ8ZXDQA 8&vxp=mtr

relay:
http://www.bavauto.com/fland.asp?part=V20-71-0003&utm_source=google&utm_medium=cse&utm_term=V20-71-0003-330I-2006-667548&gclid=CLmBo7Tq_cwCFYsmhgodRjEKmQ

and if so are there any good tutorials on how to install these?

Thanks and sorry if this has already been covered, but I have searched for a couple of hours now to no avail.

[siny528i]

I have overheating issues, the aux fan does not turn on with AC, but does run only on high when jumped at temp switch (on radiator) connector. I replaced the temp sensor switch on radiator, did not help. My friend says I should replace the relays and resistors. Are these the right parts:

resistsors:
http://www.ebay.com/itm/NEW-Auxiliary-Fan-Resistor-MTC-67-32-8-371-873-BMW-E38-E39-740i-740iL-750iL-525i-/141957084674?hash=item210d4d3602:g:cFkAAOSwZ8ZXDQA 8&vxp=mtr

relay:
http://www.bavauto.com/fland.asp?part=V20-71-0003&utm_source=google&utm_medium=cse&utm_term=V20-71-0003-330I-2006-667548&gclid=CLmBo7Tq_cwCFYsmhgodRjEKmQ

and if so are there any good tutorials on how to install these?

Thanks and sorry if this has already been covered, but I have searched for a couple of hours now to no avail.
My advice is do NOT hassle with buying and installing JUST motor or resistors.
Buy whole A/C Condenser (AUX) Fan Assembly!

[thesniffingratt]

thanks for the reply. do you mean this: http://www.ebay.com/itm/New-AC-A-C-Condenser-Cooling-Fan-Assembly-fits-BMW-E39-528i-540i-M5-1995-1998-/281801111093?hash=item419ca7b635:g:6E8AAOSwYmZXLEm L&vxp=mtr

[siny528i]

thanks for the reply. do you mean this: http://www.ebay.com/itm/New-AC-A-C-Condenser-Cooling-Fan-Assembly-fits-BMW-E39-528i-540i-M5-1995-1998-/281801111093?hash=item419ca7b635:g:6E8AAOSwYmZXLEm L&vxp=mtrDude, this... but NOT for this price!
Something wrong with their heads!

Try places like: AutohausAZ.com, PelicanParts.com or ECStuning.com.
Whatever works better for you and search for P/N 64548380780

Top price you will find for Genuine BMW is $560.
I got mine for $163

[thesniffingratt]

thanks for the advice siny. So I jumpered the aux fan so that it runs on high all the time to eliminate that as a source for the overheating. I replaced both thermostats. I have taken it on some ~2 mile rides getting up to 50mph, it has not released any steam from the expansion tank since I jumpered the fan and the temp gauge is not going above half, but it still makes pinging noises when I shut it off, and the big hose on the bottom right (left when looking in from the hood) is not getting hot while the hose on the top left (right when looking in from the hood) is getting really hot. A mechanic with a 540 said that I need to take it to the dealership, pay 200 for a diagnosis, and then $80 for them to bleed the coolant system properly with special equipment even if nothing else is broken.

So I'm wondering:
1. Has anyone else heard that you have to go to the dealer to get a proper bleed?
2. Why is the temp gauge not going above half, but the engine is making pinging noises upon shutoff?
3. Why is the bottom hose cool even after I replaced the thermostat?
4. Should I just replace the whole cooling system myself?

[siny528i]

thanks for the advice siny. So I jumpered the aux fan so that it runs on high all the time to eliminate that as a source for the overheating. I replaced both thermostats. I have taken it on some ~2 mile rides getting up to 50mph, it has not released any steam from the expansion tank since I jumpered the fan and the temp gauge is not going above half, but it still makes pinging noises when I shut it off, and the big hose on the bottom right (left when looking in from the hood) is not getting hot while the hose on the top left (right when looking in from the hood) is getting really hot. A mechanic with a 540 said that I need to take it to the dealership, pay 200 for a diagnosis, and then $80 for them to bleed the coolant system properly with special equipment even if nothing else is broken.

So I'm wondering:
1. Has anyone else heard that you have to go to the dealer to get a proper bleed?
2. Why is the temp gauge not going above half, but the engine is making pinging noises upon shutoff?
3. Why is the bottom hose cool even after I replaced the thermostat?
4. Should I just replace the whole cooling system myself?

1.You jump AUX fan to see if its motor operational. If it operates at HIGH then there is problem with your relays or MOST LIKELY resistors.
Instead of hassle with just resistors replace WHOLE A/C Condenser (AUX) Fan Assembly!

2.Did you replace Thermostats yourself OR had them replaced? Because I thought we have only 1 Thermostat. At least on my car...

3.You do NOT need Special Equipment to bleed your Cooling System and you can do it for FREE.

[thesniffingratt]

Hi Siny, thanks for the help, yes I will do that whole aux fan assembly, although I already did the temp switch for it, and the relays, but it will still only run when jumpered on high.

I didn't seem right to me that you would have to go to the deal just to bleed the coolant system, so I guess I should just go ahead and rebuild the whole cooling system?

[siny528i]

Hi Siny, thanks for the help, yes I will do that whole aux fan assembly, although I already did the temp switch for it, and the relays, but it will still only run when jumpered on high.

I didn't seem right to me that you would have to go to the deal just to bleed the coolant system, so I guess I should just go ahead and rebuild the whole cooling system?Jumpering the AUX Fan at the Temp Switch is just a TEST, showing that your AUX Fan motor is OK, but your Resistors are NOT.

For Bleeding and Overhaul the Cooling System you gotta read following topics:

Cooling System Bleeding (http://www.bimmerforums.com/forum/showthread.php?1423821-Cooling-System-Bleeding)ENTIRE COOLING SYSTEM REPLACEMENT Tips and Tricks (Very Long, Enjoy!) (http://www.bimmerboard.com/forums/posts/199986)

Enjoy!
Hope this will help!

[cnn]

I am late to this party (this thread was started 10 years ago, in 2006!).
Anyway, my Aux Fan is screeching, so time to replace it.

If you want to replace only the motor, then it is now Four Seasons 75720 (bought on ebay for $60).
If you don't want to deal with the wiring and heat shrink tubing, buy a new Aux Fan Assembly.

1. Tools are: 8mm socket, 10mm socket and 13mm socket.
- Torx 50 (not Torx 45).

2. Heat shrink tubing.

2. Watch youtube video on how to remove bumper by bimmermerchant.

3. READ the DIY by daw on bimmerfest.

4. Once the bumper if out, removing the Aux Fan assembly is straightforward (10-mm nuts).

5. Installing the new motor is a bit tricky. WATCH carefully the factory setup, then reproduce it.
- Basically routing the wires properly.
- In the connector: push the Brown and Black-Blue wire out of the connector (push them out).
- Make sure you mark which is which, when in doubt, look at the other side of the connector for the Brown Wire etc.
- For the Black-Blue wire: cut it and use a butt connector, don't solder it. Slide the heat-shrink tubing in first!
- Then use small amount of heat to shrink the tubing, don't burn the wire!
- Note the tab on the triangular piece and how it faces the C-Clip.


That is all folks. A few photos for those who need them...


577432


577433


577434

[nikatkimber]

Hey guys, for the reference of future readers, just in case you change cars, could you note whether your car was 98 or older, or 99 or newer?

The fans are different. Jumping power to the newer, PWM controlled fan on the 99+ cars is NOT a valid test, and depending where you connect power, you could fry an otherwise good fan.

[peterintheyvr]

Hi, I've isolated it down to something in the Aux Fan circuit that is causing my battery to die after a few days. Any idea what it might be (resistor pack or relay)? When I disconnect the fan connector (just in behind the grill and in front of the aux fan), the battery no longer drains/dies. I'm not sure if the resistor pack is shorting somehow or if one of the relays is kicking on occassionally. Any help would be much appreciated.



as many of you know, auxiliary fan failure is one of many weak points on most bimmers. just to remind, it's the electric fan mounted in front of the A/C condenser (that is located in front of the radiator) that sometimes makes our cars sound like an airplane during acceleration.

the aux fan is always on (low speed) whenever A/C compressor is on, to cool off the refrigerant flowing through the condenser (using A/C without properly functioning aux fan can cause compressor failure). when it's very hot, the fan may go into medium or rarely high mode, which really sound like an airplane, to provide some extra cooling for the cooling system.

additional info: the connector for the fan consists of four wires:
brown-ground
blue-12v direct to fan, high mode
red-12v through single resistor to fan, med mode
black-12 through both resistors (in series) to fan, low mode

you can notice the first problems with the fan if it's not coming on when A/C compressor is on. the possible reasons of this are:
-bad fuses: #7,20,22 or 75, the last one being under and behind the glove box comp.
-failed resistor(s)
-failed radiator temp switch
-failed fan motor
(-rarerly failed relay)

most often it is either bad resistor pack or fan. it's worth mentioning that a failed resistor may often cause the fuses to blow. the reason for that is that with failed resitors the fan is not working on low speed and on the occasions it is kicking into high there is too much current draw.

to check whether it's the mulfunctioning resistor, (assuming all fuses are OK) you can just jump pins at the temp switch, or connect 12v DC directly to the fan connector (brown-ground, blue-12v positive). if the fan kicks in high mode, the problem is the resistor pack ($50-60).
if the fan is not working at all, the second method (direct 12v) will tell you whether the fan motor is the culprit.

most online vendors want almost $60 for the resistor packs and the fan motor alone is a whooping $200. preety steep, considering the entire fan assembly costs $300, though seeing the size of the motor and how powerfull it is, no wonder it costs so much.
below is the pic of the fan motor from one of my favorite online vendors, charging around $190 for it
http://i10.photobucket.com/albums/a139/PENER/e39fanonline.jpg

however, I have been able to spot a tremendous deal for the very same motor at Autozone. the same fan (SIEMENS PM9047) they sell for ONLY $82!!!
below it the fan motor I ordered from AutoZone
http://i10.photobucket.com/albums/a139/PENER/P1040006.jpg
as you can see, it's the very same fan, and actual replacement part for our cars. comes terminated with the prongs that slide into the connector and even has a part of the blue wire stripped in place where resistor packs connect to it

some pics of my old fan and new replacement
http://i10.photobucket.com/albums/a139/PENER/P1040007.jpg
http://i10.photobucket.com/albums/a139/PENER/P1040008.jpg

(I'd like to add here, that upon removal of the old fmotor, I found it to be still spinning with 12v put to it, although it did not work during the earlier tests. however many owners can confirm similar results with their old units. but now, knowing that you can get the new motor for only $82, it's no brainer...)


replacement of the fan resistor pack or entire fan assembly requires the bumper to be removed first together with both headlights and the (kidney) cowl. sorry for the crappy pic (low light conditions) BTW in case someone wonders where is the Secondary Air Pump (bottom left corner of the pic), it's been replaced with new type pump and retrofitted under the hood.
http://i10.photobucket.com/albums/a139/PENER/P1040011.jpg

good luck

[OldGringo]

Just replaced whole aux fan unit. Not a hard job, old one was dead.
Worth noting, got a unit from AutohausAZ, and it came with resistor pack installed. A Behr OEM, perfect fit, shipping included for $158.

[dougp]

Hi, I've isolated it down to something in the Aux Fan circuit that is causing my battery to die after a few days. Any idea what it might be (resistor pack or relay)? When I disconnect the fan connector (just in behind the grill and in front of the aux fan), the battery no longer drains/dies. I'm not sure if the resistor pack is shorting somehow or if one of the relays is kicking on occassionally. Any help would be much appreciated.

Score! Finally found someone having the same issue as I am with the aux fan. According to your signature, you have a 1999 e39 (as do I) which means that there is no resistor pack and no set of three relays that control fan speed. Input to the fan is simply ground, 12V, and a PWM signal from the ECM that controls fan speed. I am assuming the problem is something to do with the fan motor/controller that is causing it to draw current (about .5A) when the car is off, in which case I'm guessing that the most reasonable approach is to just replace the fan ... but I'm not certain yet.

-Doug

[ninetyseven1]

Im at my wits end! I have replaced both reistors, tried 2 different BRAND new relays in the ebox, and ALL fuses in glovebox are good and fuse 75 is good. The fan low speed only comes on when i remove the relay and jumper pins 87 and 30, i can make high speed come on by pumping the pins at the temp switch connector at the radiator. What is going on?? Does the coolant have to be at a certain temp for even the low speed to kick on? maybe the DME measures this?

[Barnesautos]

Don’t know if it’s specific to your car , but you get the idea of the wiring and switches and the relay.

Low speed
630255

Medium speed
630256

High speed
630257

[jjones540]

So I have a 2003 540i that has been overheating in traffic at first I thought it might be the fan clutch, and still haven't checked the fan clutch while the car is warmed up, but while poking around the auxiliary fan I found that my wires have no plugs on either end and whoever I got this car from nutted two of the three wires on either side together and left the other two unutted. I only have 6 wires, a red and yellow, brown, and black from the sensor switch and a red, green, and black from the fan. The red and yellow wire was nutted to the red wire and the green to the black. When I touch the brown wire that is left over to the black wire coming from the fan the fan spins at what I assumed to be its highest speed like it's on crack this happens whether my key is in and on or laying on the grass next to me also the wires heat up. I tried other combinations and got either nothing or the fan trying to spin backwards... any answers?

[ninetyseven1]

So I have a 2003 540i that has been overheating in traffic at first I thought it might be the fan clutch, and still haven't checked the fan clutch while the car is warmed up, but while poking around the auxiliary fan I found that my wires have no plugs on either end and whoever I got this car from nutted two of the three wires on either side together and left the other two unutted. I only have 6 wires, a red and yellow, brown, and black from the sensor switch and a red, green, and black from the fan. The red and yellow wire was nutted to the red wire and the green to the black. When I touch the brown wire that is left over to the black wire coming from the fan the fan spins at what I assumed to be its highest speed like it's on crack this happens whether my key is in and on or laying on the grass next to me also the wires heat up. I tried other combinations and got either nothing or the fan trying to spin backwards... any answers?

The Aux fan has nothing to do with overheating, it is to keep the air conditioning condenser cool.

[JimLev]

If your Aux fan isn't working and you have the AC on it can overheat, especially in the summer.
Your Aux fan should only have 3 wires, +12v, ground, and a PWM wire that controls fan speed from the DME.
Sounds like someone used fan from a non tu engine or used an aftermarket fan.

[Junglist]

I can't speak for the older style 3 phase fan but for the newer variable speed electrical aux fan there is a way to test if it's working using INPA.

Strangely it's NOT found by selecting E39 - 5 Series --> Body --> Air conditioning IHKA IHR

Instead you can get to the test by choosing E39 - 5 Series --> Engine --> (Choose your Engine Type)

In my case this is ME 7.2 for M62 MJ 99

Once in the main menu choose <F6> Activate --> <F2> Activate relay TEV --> <F3> el. fan

If the fan is working you'll hear it click a few times in the first 5 seconds before it spins up and increases speed to max over about 15 seconds or so before cutting out and slowing down to a stop.

If the fan works it will point to the culprit for the AC not working elsewhere... In my case to the system not having enough gas pressure.

This can also be verified in INPA...

E39 - 5 Series --> Body --> Air conditioning IHKA IHR

<F5> Read Status --> <F1> Analog input

The voltage for the pressure sensor is how the DME determines the pressure as one of the conditions that must be met for activating the AC compressor clutch via a final stage control.

652310

I would have attached the whole document for the 2001 changes to models that this image is from but it's over 1MB and it gets blocked.

[Young 23]

Hello guys,

Here's what I ve learned (thanks edjack from UnofficialBMW and Jim Cash from RoadFly) with some of my editing:

Double Temperature Switch 91/104CEL (located on Radiator) activates the AUX Fan when coolant reaches above average temperatures:
91C - Low speed
104C - High Speed

AUX Fan operates on 3 modes: LOW, MEDIUM and HIGH.
NOTE: Newer E39's may have a variable speed fan and these tips may not be exactly what you're looking for.
These tips are accurate for troubleshooting a 1998 540iA with a Nov 97 build date.

AUX Fan comes on at LOW mode/speed whenever the AC is ON by an input from the AC controller and the engine computer combined AND the outdoor temp is above 10C - as shown on the display in the instrument cluster AND it supposed to stay on ALL THE TIME.

Two days ago in order to check my newly installed AUX Fan I:

- Disconnected the 3 wire harness that goes to the Double Temperature Switch 91/104CEL (located on Radiator):
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/021.jpg

- Started the car;
- Using small paper clip...
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/022.jpg

...I connected BROWN wire to the BLACK wire with RED Stripe - AUX Fan started to spin at MEDIUM speed;
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/023.jpg


- Then I connected the BROWN wire to the BLACK wire with the WHITE Stripe - AUX Fan started to spin at HIGH speed;
http://www.cyberforma.com/auto/issues/bmw/528i/1998/hvac/condenser/900x500/024.jpg

- Shut the car down and reconnected the harness to the switch.

By jumpering at that point you are operating the relays that provide the power source to the fan.
Relays are in the E box (under the passenger side microfilter).

So my AUX Fan is Ok, but I wish I knew this trick and used it on my OLD one...

IF the Aux fan did NOT run at any speed, then I would first suspect that a fuse is blown.
IF you've checked the fuses then motor may have failed.

IF the AUX Fan only worked on the highest speed, then I would suspect that one or both of the resistors or relays that control the lower speeds have failed (no resistors are used for the highest speed, but a relay is).The resistors that control the lower speeds are located on the AUX Fan Assembly.

IF you are experiencing overheating and the fan worked flawlessly, maybe the temp sensor (the one that you disconnected to jump wires at) has failed.

PS. Yesterday morning it was moderate outside. About 52F. I started the car and my AUX Fan went ON at LOW speed.
I saw its spinning like this first time since I bought my car in 2007. Or maybe I've never noticed...

I just wanted to say I used your method of testing the fan (after I installed the same unit you did with no signs of life) and it worked! It does not turn on on its own, so that’s a mystery, but at least now I know the fan itself works on both speeds and it isn’t defective. Did you find out why it doesn’t turn on on it’s own? I replaced the temp switch and checked the fuses (the relay not yet) but it won’t come on. My ambient temp sensor is missing, but upon further inspection I realized the ac high side pressure switch is broken (literally, idk who did it and how). Could these cause the inability of the fan to function on its own?

[Junglist]

If the fan and resistors are good then I'd check the relays.

[Young 23]

If the fan and resistors are good then I'd check the relays.

Cool thanks!

[rbelton]

I just replaced the entire fan assembly on my 2002 530i. The fans on the earlier 528 models are different than the later model 525/530/540 in design. Here's the DIY guide for the replacement, which involves removing the front bumper.


https://youtu.be/CazRTB9J0uw

link: https://youtu.be/CazRTB9J0uw

[camtman]

Hello all, hate to revive a dead thread like this but I am having issues with my aux fan as well.
My car is an 02 540i. The fan does not turn on at all, even with A/C on in 100 degree (F) heat. The fan spins freely, and it does spin on start up for computer test. No errors are thrown in the computer either.
Where should i look first?

[StephenVA]

Jump back to Post #18 as your's is a later model with a different Aux fan than the earlier "preface lift" models. The DME sends a square wave signal to the fan to increase or decrease speed. There is always 12volts at the motor. IF NOT then check/replace fuses and relays. Any scanner (Foxwell 510 for example) will show you where the fault is. Fan assembly, Fuses (NO POWER) relays (no Power).

Get a scanner, a volt ohm meter and TEST, don't guess.

[Samsam15]

I thought I would add that I made a thread about repairing the motors for free, the title is "Fixing a Early E39 / E38 Auxiliary Fan / Pusher Fan Motor For Free".

[CFLip2X]

I have read this entire thread and trying to figure out what is happening with my Aux fan. In short my 01 525 overheated I found the 19yo radiator developed a crack. Replaced the radiator hoses and thermostat as well as installed an electric Spal fan.

Using an Ultragauge my temps max around 215F which lead me to check my Aux fan. I noticed it was not spinning when I would turn on the AC. If I turn the AC on and disconnect the fan and plug it back in it sometimes spins for a bit but then stops. I am hoping its doing this because of a loose wire or maybe a failing fan.

I ended up getting a new Behr fan nd want to test the fan before removing the bumper. With the car and AC running I try to connect it but the fan does not spin at all. It could be due to not having a lot of slack and a loose cable but could I be doing something wrong? I have tested the connector with a multimeter and was able to detect 12v and ground. I am going to borrow a multimeter that can detect Hrz to see if I am getting a PWM signal. Luckily its getting into winter and I still have the electric fan but I would still like to get this figure out.

[JimLev]

Welcome to the forum CFLip2X.
With the AC on the aux fan isn’t going to come until the temp sensor in the lower radiator hose gets hot enough for the DME to send PWM signals to the aux fan.

[CFLip2X]

Welcome to the forum CFLip2X.
With the AC on the aux fan isn’t going to come until the temp sensor in the lower radiator hose gets hot enough for the DME to send PWM signals to the aux fan.
Thank you. The car should have been up to temp I tested it after my drive to work. I did replace the sensor the old one had a bad o-ring so decided to get an extra since I was not sure of the type of ring. Even if it is not up to temp I should be able to connect the old one assuming it still works and just use a heat gun to warm it up and trick it switch on the fan. I have been so busy haven't had time to test with a multimeter will try today.

[siny528i]

AUX Fan comes on at LOW mode/speed whenever the AC is ON by an input from the AC controller and the engine computer combined AND the outdoor temp is above 10C - as shown on the display in the instrument cluster AND it supposed to stay on ALL THE TIME. In other words, if you turn AC on while its LESS than 10C (50F) outside it will NOT engage, if more than 10C (50F) - it will...

[lowlife89]

Hi,

Saw a fan error:

https://i.postimg.cc/LYc3jp2P/Screenshot-20230715-081735.png (https://postimg.cc/LYc3jp2P)

Fan moves alright by hand but will only jump a little when activated with INPA (80% here):

https://youtu.be/HMjtZRVaseU

Is there something else to check or is the fan surely broken?

Thanks.

[BimmerBreaker]

I posted this in another thread recently and seems it belongs here too:

https://static.wixstatic.com/media/d1ff59_6ddb23eb95e54aa995f7afb14141e9c4~mv2.png



The DME will check the operation of the aux fan at startup and periodically during operation. If a fault is detected (doesn't move at startup test) or fails during operation, it will disable A/C

The aux fan (and A/C) will also not run if the car is too cold. So, if your ambient temperature sensor is faulty - the car will think it is -40 degrees outside, and it won't run the A/C OR the aux fan.

The most common failure mode I have seen regarding PWM fans is the control wire, they often get brittle and break near the fan connector. They may work intermittently. This can often be diagnosed with INPA by commanding the fan on and then adjusting the PWM fan wire, moving it around - if some positions it works, others it doesnt, the wire is the problem.

I see about 5 wire failures for every other type of failure related to the aux fan. It's always the first thing (along with ensuring ambient temp is reading correctly) I check on cars with A/C faults or aux fan faults.

The aux fan can cause overheating. The fan clutch isn't always enough to cool the engine on it's own. It's usually enough to keep it from going nuclear, but if it's hot enough, a lack of working aux fan can cause the car to exceed the intended operating temperature of the engine. It is a "supplementary cooling fan" per BMW. Used for A/C, but also for cooling.



Hi,

Saw a fan error:

https://i.postimg.cc/LYc3jp2P/Screenshot-20230715-081735.png (https://postimg.cc/LYc3jp2P)

Fan moves alright by hand but will only jump a little when activated with INPA (80% here):

https://youtu.be/HMjtZRVaseU

Is there something else to check or is the fan surely broken?

Thanks.

As it sounds it works intermittently, I would check the PWM fan control wire (the small wire, it goes to DME X60004 pin 4)