Hey, i have a 2000 323i and recently the air conditioner has been acting up. It will work fine for a little while, but then suddenly start blowing hot air for a while. And then suddenly start working again. Sometimes this problem lasts for a few minutes and other times it can last 20-30 min. Any ideas wat could be causing this? Also, i think one of my external temp senors is missing, on the left side. could this be the problem? if so, where can i buy a replacement because i have not been able to find one.

do you have a temp reading in your instrument cluster. If so and the temp sensor is gone. The temp reading should read at liek -40 degrees. If this is the case then you will have to get that sensor replaced.

Hey, i have a 2000 323i and recently the air conditioner has been acting up. It will work fine for a little while, but then suddenly start blowing hot air for a while. And then suddenly start working again. Sometimes this problem lasts for a few minutes and other times it can last 20-30 min. Any ideas wat could be causing this? Also, i think one of my external temp senors is missing, on the left side. could this be the problem? if so, where can i buy a replacement because i have not been able to find one.
:woot: Dude, I'm having the same problem with my AC in my 00 323i. My problem started about a year after I replaced my AC Compressor and I'm told by my Independent bimmer service provider that it has to do with the connection between my Compressor and my unit which sometimes loses it connectivity and begins to blow warm air. I orginally thought it was a refrigerant problem but I now have to get the wires cleaned and connected properly to make the problem go away. Just my two and a ahlf cents worth. Hapy Motoring...
:atom

First order of business is to find out if the A/C is fully charged. If not, get it charged and the problem should go away. If it comes back, then you've got a leak that will need to be addressed. Have whoever recharges the system to add some leak trace dye. Some dealers won't so this, so ask in advance. They'll tell you that BMW recommends against using leak trace dye for fear of future complications, but in 15 years of using dye, I've never had an issue arising from it's use. So find a shop that will recharge with dye so if the problem does return, the leak will be much easier to find.

I had the same problem in my 2000 E46
Turned out to be a big diecast metal sensor ( looks like a bunch of high rise buildings) wich fits in the side - in the air path
A new unit costs around AUD300 ( I got one from a wrecker for $100)
Bruce

I had the same problem in my 2000 E46
Turned out to be a big diecast metal sensor ( looks like a bunch of high rise buildings) wich fits in the side - in the air path
A new unit costs around AUD300 ( I got one from a wrecker for $100)
Bruce
It's not a sensor, it's the final stage resistor for the blower motor.

Hi
I am sure your are correct as it looks like it gets hot - and it was a chore to replace ( you need fingers on the ends of your fingers I reckon)
I have another problem with the same air con. It seems to ice up - fan blows but no air comes out ( this happens after 10 15 min)
If I turn AC off it blows progressively stronger after 2 mins or so, then when I turn AC on again, blows cold
Then this happens again
Is there an anti icing sensor ???
Bruce

Hi
I am sure your are correct as it looks like it gets hot - and it was a chore to replace ( you need fingers on the ends of your fingers I reckon)
I have another problem with the same air con. It seems to ice up - fan blows but no air comes out ( this happens after 10 15 min)
If I turn AC off it blows progressively stronger after 2 mins or so, then when I turn AC on again, blows cold
Then this happens again
Is there an anti icing sensor ???
Bruce
The most likely cause of any air conditioner icing up is a low refrigerant charge.

i have a 2000 323,the a/c is fully charged, where are these sensors you guys talking about and wires that may need cleaning to check it out?

Yep might be the final stage resistor for the blower.

the heat issue is the FSU, case closed. there's a DIY some posted on here probably 700 times. Just do a search for FSU, i think the second search result will have a link to the DIY.

I just did it myself about a week ago, took maybe 30 minutes tops, kinda a pain in the ass to do, but well worth it, plus the part is only like $100, so, might as well give it a shot.

damnit, looks like a spoke to soon. a week after replacing my FSU it's blowing half hot air again. Son of a ...

Mastamind518 did you ever get this resolved? Was it the external temp sensor? I believe I just lost mine on the left front and now my dash reads-40 for temp and always beaps when I start the car and now the AC is doing what you explained it all worked fine before? respond and let me know if you fixed, thanks!

Your auxilary fan is probably dead. The fan should turn ON whenever the A/C is ON.

any advice on an AC that sometimes does this odd hissing noise...like you know how AC normall sounds, well lately mine goes through stages where its like "broooom brooom broooooooooooom broooooooooooooom brooom brooom....normal sound" did that make sense?

Mastamind518 did you ever get this resolved? Was it the external temp sensor? I believe I just lost mine on the left front and now my dash reads-40 for temp and always beaps when I start the car and now the AC is doing what you explained it all worked fine before? respond and let me know if you fixed, thanks!

If it says -40 then it's the sensoror or it's wires... nothing else

Guys. If your outside temp sensor is gone (crunched a curb?) or broken, and you have the dash display reading of -40F, your AC will run hot and cold, sporadically. Trust me. I've been living with it for about a month.

Do this. Jack up the car and remove the left front wheel. Remove the fender liner in front of where the wheel was. (Two bolts at the top of the liner, two bolts under the front bumper.) Inside there, you'll see where the temp sensor used to live, down on the bottom of that plastic fender liner. Now, find the wires that used to be attached to your outdoor temp sensor. They may be hanging there, or you may have to unwrap some black tape from the wires that go to your fog lamp. The wires you're looking for are probably blue with thin red tracers. (Thus far, I owe what I know to a couple of very helpful people on this forum.)

When you find the two blue wires that used to be attached to your sensor, short them together and wrap them with black tape. Start your car and look at the dash display. I'll bet you a hundred bucks that A) the display will read something like 122F, and B) your AC will work normally.

This is only based on my own experience, over about two weeks of hassling with it. I've gone through two new sensors, both of which still give me the -40F reading, meaning that the system isn't seeing the sensor. Also, during that time, my AC has run cold, hot, cold, hot.

Somebody said something earlier about checking your refrigerant level. Please tell me how the AC would EVER run cold if it didn't have enough refrigerant?

Sorry if I sound like I'm ranting, it's just a very frustrating thing, being it's July in Missouri and hot as hell. I'm just saying that if you want your AC to work and your outside temp sensor isn't working, try shorting those two wires. Works for me.

the final stage blower resistor controls the speed of the motor, and nothing else. it will have NO EFFECT on the temperature of the air, or the climate control functions, only the blower speed.

What he said.

I'm just saying that if you want your AC to work and your outside temp sensor isn't working, try shorting those two wires. Works for me.It'll work until Winter, when the defrosters won't work.

It'll work until Winter, when the defrosters won't work.

I was wondering about that. Thanks for the info.

NickDeck, excuse the ignorance but when you say "short the wires together" your talking about splice'n them, twist the two bare wires together and then wire nut them or tape them up, right? Learn new lingo everyday. Thats good for now but like they said above how do we fix come winter when and if the defrost doesn't work? You said you have replaced the sensors with no results.

+1 on the external temp sensor

I didn't think that it should have an effect on the a/c temp either, but 10 seconds after ripping mine off on a parking block in Las Vegas my a/c, which was working fine, all of the sudden went ballistic. I'm about to "short" my wires, I'll update to see if it makes a difference.

I had the same issue w/02 325ci. I took it to the stealership and it ended up being some type of resistor. The guy knew exactly what it was as soon as I described it to him. Apparently it is a common issue w/E46. Stealership charges $250 to replace it but you can probably avoid the $110 hourly labor charge with a little diy

All you need to do is take it to an experienced mechanic or ask and order the part

Now my 2001 325 a/c is blowing hot, where is this FSU located? I just called the dealer they have it in stock $125, going to go pick up.

Now my 2001 325 a/c is blowing hot, where is this FSU located? I just called the dealer they have it in stock $125, going to go pick up.

It's inside the dash under/behind the glovebox. Also, many of our supporting vendors have them for much cheaper ($70ish) if you don't mind waiting a bit longer for shipping.


However,

the final stage blower resistor controls the speed of the motor, and nothing else. it will have NO EFFECT on the temperature of the air, or the climate control functions, only the blower speed.

If your final stage resistor is bad, your fan will blow at erratic speeds, but the air will be the correct temperature. If you turn on the A/C and it still blows hot, you have a different problem than the final stage resistor:
1. Bad external/ambient temp sensor
2. Improper settings on climate controls (have you adjusted the wheel between the two front center vents?)
3. Low refrigerant charge in A/C system
4. Malfunctioning climate control unit
5. Stuck dampers/baffles/panels inside the vent system