Hi all,
I have a 86, Production date of 10/85 and the blower for the heat does not work at all and when the A/C is on the blower works on the high setting only.
I have a kit to rebuild the heater control valve and want to fix the blower issue at the same time. Has anybody else had a similar occurrence?
Thank you one and all for your replies.
EddieE
86 635CSI
83 320Is
73 3.0CS
87 MBZ 300SDL
95 GMC Sierra
If the Heater Blower does not work in the "Max" position, then it is either a bad blower motor or a bad Blower Select Relay.
If the A/C Blower (it's not the same as the Heater Blower) only works in the "Max" position, then the power transistor at the A/C blower is probably bad.
If you notice, the "Max" position by-passes the speed control and sends full power direct to both of the blower motors and it is the "A/C Switch" which energizes (or not) the Blower Select change-over relay that selects which blower to operate by grounding one or the other.
Do you have a Multi Meter and do you know how to use it? Some simple troubleshooting is called for to figure out the exact cause.
( If the image doesn't open: http://www.stormpages.com/countchocula1/bmw/etm158.htm )
Yes I have a simple multimeter and have some experience with it.
Volts,amps,ohms, and diode checker are what I have used before.
Ok. I'd start with the heater blower motor (easiest to get to), it's under the scuttle in the engine bay. Here is a thread with pictures on how to access it (and change the transistor for variable speed, if need be, but first you have to figure out if the motor is good): http://www.normgrills.net/bcg/Blower_Transistor.htm
(See diagram above)
With the key on, and the Speed Control set to "Max", check for power at the BU/BK wire at the Blower Motor and for continuity to ground at the BR wire.
If there is no continuity to ground, then the Blower Select relay may be bad. If there is no power, then the micro-switch in the blower Speed control or the wiring from it may be bad. If there ia power and ground, pull the motor and check it on the bench with a 12v power source.
Have you downloaded the ETM yet?:
ETM (Electrical Troubleshooting Manual, aka "wiring diagram"). It is a very good manual, everyone needs to have this, you really can't work on the car without it. Here is a page with free downloads of ETM's (PDF files -13 to 20 MB) for various years ('82 to '01) and models (3/5/6/7/8/Z) of BMW's:
http://wedophones.com/BMWManualsLead.htm
Last edited by CW6er; 06-24-2009 at 08:35 PM.
HI,
Did what you suggested and found that the brushes in the motor are not making contact. When I pinch the two brushes while the motor is hooked to source and ground the motor works. Went to the scrapper and found a very good used motor. Installed it and now the heater blower works on high only. A/C blower works on high setting only. I changed the resistor located with the heater blower also. I soldered in a new resistor.
Question, is it possible to install the resistor 180 degrees out? Now that I think about it I did not check to make sure it is oriented correctly.
I also downloaded the manual for my car.
Thank you very much for your help.
Hello again,
I picked up a blower speed selector switch from a 1983 320i while I was at the scrapper. Can this be used in a 635csi ? There was only one six series in the entire yard and the switches were already gone.
Thanks again
EddieE
Last edited by FlyWulf; 06-24-2009 at 09:02 PM. Reason: Automerged Doublepost
It's a transistor, not a resistor.
The pins are offset so it is impossible to mount it any way but correctly and the connector spades differ too so you can't go wrong there either.
Which transistor did you solder in ? NPN what number ?
According to Real OEM the switch from the 83 320 won't work. Here's the cross model compatibility list and a picture of what the correct switch looks like.
Part 61311381317 (SWITCH BLOWER) was found on the following vehicles:
E24: Details on E24
E24 628CSi Coupé, Europe
E24 635CSi Coupé, Europe
E24 M635CSi Coupé, Europe
E28: Details on E28
E28 520i Saloon, Europe
The transistor number that I installed is NTE 181. Installed it by the heater blower under the plastic cover under the hood.
EddieE
Hello again,
So far I have made some progress. At present I have both blower motors working but only on the high setting. Rebuilt the heat control valve and I get plenty of heat but can't control the temperature. I moderate the heat with the flap control sliders. I can lower the amount of heat to an acceptable level that way for now. All electric components for the AC system seem to be working as they should. I get a little bit cooler air when I select that system on.
Do you think that I need to replace the temp selector and fan speed selector switches at this time? They are kinda pricey items.
thank you all for you input, very much appreciated.
EddieE
Last edited by FlyWulf; 06-24-2009 at 10:40 PM. Reason: Automerged Doublepost
I'm not familiar with the NTE line but I note that that is what the normgrills guy used so I'll assume it's appropriate for the application.
I think then that you're on the right track in looking for a replacement switch as since both the A/C and the heater blowers work only on high then the blower relay that CW described is OK but the rotary switch potentiometer aint.
I'm curious....with the rotary switch set to mid point, key in position 2 and the a/c NOT selected how much if any voltage do you measure at the plug to the heater blower transistor ?
Hello again,
When I installed my new transistor I used a plastic gasket that came with the new unit. It is installed between the resistor and the mounting plate. Could that cause it not to function properly? I read the other thread about installing this part and it mentioned using heat sink grease. What is that?
Cheers,
EddieE
What and where is the plug to the heater blower transistor?
EddieE
What and where is the plug to the heater blower transistor?
EddieE
Last edited by FlyWulf; 06-24-2009 at 11:04 PM. Reason: Automerged Doublepost
If both the heater blower and A/C blower only work on high, then it is probably the transistor in the Blower Speed Control that is bad (the transistor in the heater blower may not have been bad and may not needed to be replaced, but it won't hurt).
Here is a download for a 270k PDF file for fixing the Blower Speed Control Transistor and Rheostat:
http://bigcoupe.com/phpBB2/download.php?id=2989
The heater valve is an "all or nothing" type valve. If the power is removed, the valve is full open. Apply power and the valve goes full closed. The temp is controlled by the Heater Regulator cycling the valve on and off. (Note: power is applied to continuously to the valve, it is the ground from the valve that is controlled by the Heater Regulator)
With the Heater Regulator in the "Full Cold" position the power should be applied to the heater valve continuously (path to ground open) to keep the valve closed, so if you can't turn the heat off in this position, something is wrong.
There are also two sensors, the Interior Temperature Sensor in the drivers kick panel that has a vacuum line that can come off and the Heater Temp sensor that need to be checked.
( If the image won't open: http://www.stormpages.com/countchocula1/bmw/etm157.htm )
Hello again,
I could not view the attached file. The other site would not allow it.
Thank you again for your replies very helpful.
EddieE.
This is such a great place for us to get help. Hats off to CW6er and those like him.....
All I recall is dirt, sky, dirt, ambulance....
My A/C doesn't work at all. But my heater only works at full. I also cannot open that PDF from bigcoup, but it would be very helpful. If you could email me the pdf I would be more than happy. THankss jphjones@hotmail.com
agreed catseye..........
Last edited by jphjones; 06-25-2009 at 02:28 PM. Reason: Automerged Doublepost
No, I don't think the plastic gasket would cause your problem although I've never used such a newfangled thing and wouldn't much trust it to do the job in the long run .When I installed my new transistor I used a plastic gasket that came with the new unit. It is installed between the resistor and the mounting plate. Could that cause it not to function properly? I read the other thread about installing this part and it mentioned using heat sink grease. What is that?
If you look at the pic I posted of my transistor mounted you can see the outline of some white goop under it.....that's heat sink grease. It comes in a tube, serves to help dissipate the heat generated by the transistor and is available probably from the same place you bought your transistor from.
The voltage would be measured at the female connector (can't remember if it's the fat or thin one) to the transistor mounting bracket spades but I was only asking as a personal favour for my own purposes as I'm trying to figure out a wierdness in my own heater blower's functioning so I'm surveying everyone I can to find out the results of this voltage test.
As for your heater valve insert you can try bench testing it with a 12 volt source to see if the plunger plunges or not. Also check that the rubber diaphragm on the end has no tears. Given that it's new it should plunge and it shouldn't be ripped but ....
Hi again,
Could you also e-mail me the Pdf for the transistor change instructions.
Thanks a million!
EddieE
EEEEADI@ail.com
Last edited by FlyWulf; 06-25-2009 at 07:12 PM. Reason: mail address
I have not been into that circuit, but the body of a TO3 transistor is the collector, so it should be electrically connected to something. It could be that the screws make that contact. I will actually need to do this repair in the future, so I will report then.
My point being that using the plastic gasket down could be an issue if it did not have one on the original. The supplied gasket could also be a heat sink.
Last edited by tlister67; 06-25-2009 at 08:09 PM. Reason: Automerged Doublepost
Hello again,
I have changed the transistor in the fan speed control and the fan works correctly on both the heat and AC. Outstanding!
I lubed the rheostats on both the temp and fan and they both still grind when they are turned.
How would I find the part numbers for these two parts?
Thanks again,
EddieE
Last edited by FlyWulf; 06-26-2009 at 09:56 PM. Reason: spelling
Glad it worked out! What transistor did you use? Where did you find it? Apparently the originals are a bit hard to find.
The PDF has the OEM part number for the rheostat in the temp control (it's not listed separately in the parts catalog as a BMW part), but unfortunately, they don't seem to be available from the OEM, according to the PDF.I lubed the rheostats on both the temp and fan and they both still grind when they are turned.
How would I find the part numbers for these two parts?
Again hello,
I still can't find the PDF at the other site. Is it under a different authors name?
EddieE
Yes, it is. The link above didn't start a down load?
It's in the Tech Articles, here is the thread (scroll down):
http://bigcoupe.com/phpBB2/viewtopic.php?t=2465
Thanks for the new link it worked. A great article on the topic.
The resistors I used were were from two different manufacturers. An an interesting note about them.
I used a NTE181 for the heater blower resistor. It was available at a local independent electronics shop. Cost $9.00! I brought both my circuit board from the fan control as well as the micro switch. I wanted to renew both while I had the unit apart. I could not get either at my local shop so I drove approx 20 miles to another much larger distributor to find these components. No luck. The number that was cross referenced to the NTE brand was obviously not the right part. The clerk at the first shop made an error reading the number. He read the transistor number as 80543A when it was actually BD543A. I was on a wild goose chase at this point. I drove even further to get to a radio shack store which carries the TIP3055, essentially the same transistor from a different manufacturer. In the end I could not locate the correct number for NTE products for the blower control transistor or the microswitch. The microswitches available at the stores were similar in dimensions but had additional blades. In other words, not a match. In the end I installed what I have and have working fans for both the heat and AC which is just great! The heat works also. Now off tto the scrapper to get some of those clips that hold the flapper control cables in place. Lost one while removing it. Shot off like a bullet!
Next project, make the AC blow cold again.
Thanks all in the future I will make it a point to take Pic's.
Hi, I am having a similar problem with my heater blower. My auto electrics experience is extremely limited.
I have replaced the transistor with an identical replacement in my 1982 635csi, and I have tested the 2 relays I found behind the blower control panel (Which both work). I haven't been able to test them under load, though (Don't know how).
I also replaced the heater blower fuse. But the heater still only works on high.
The control I have is the progressive dial version.
Could there be something wrong with the dial?
Please can you help?
Which transistor did you replace? There are two, one at the blower motor and one behind the dash.
I have now replaced both transistors. One under the right of the dashboard for what I assume is the A/C blower and one under the rain shield next to the engine compartment.
I also tested the relay behind the glove box, but I think it works fine.
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