Hello to all. I guess that I am just brain dead. I have been trying to figure out how to make the heat work on a 1990 750iL. I read and re-read the owners booklet, but still can get it through my thick head, just how to make heat come out of the vents, anywhere. I tried what I read in the owners booklet, but it leaves a lot to be desired, as far as actually stating:
1. Do this
2. Do that
3. Turn this wheel
ETC. You get my point?
I am at a loss about getting heat in the car. Any ideas would be greatly appreciated. Thank you very much, Tony.

Tony,
turn the driver side thumbwheel to the highest position over a resistance till it cliks.
That is the emergency function if the control fails. Driver side max with click overrides any settings on passenger side. With this click you have cut out power to the heater valves and they should be fully open and only hot air should come.
If that does not work, your heater valves are stuck in closed position.
Give them a whack with a hammer, sometimes they get lose again. Or disassemble them and clean them.
I disassembled the valves from one of my parts car, and I found out that the 'clever' pre-owner has used some coolant sealer stuff, and that looked like this
http://dd.jpn.org/BMW_HP/20040618/solid.jpg
Here I have posted how to clean them, pics
http://www.7-forum.com/forum/24/heizungsventile-reinigen-44167.html

You can also disconnect the plug (3 pins) from the heater valve to test. No power=valves should be open.
Testing the heater valves and the control
http://www.bimmerboard.com/forums/posts/380566/
More info here on heating and rear defroster
http://www.bimmerboard.com/forums/posts/425604/
http://www.bimmerboard.com/forums/posts/220273/

any more questions, please let me know :)

Hi Erich, I will give it a try the next time I am around the car. I actually did turn the thumbwheel on the drivers side past the detent, but there was no change in heat, also did it on the passenger side as well, no heat either. I had posted a question before, if it was normal for a clicking sound to be coming from the heater valves, and was told that this was normal for them to do this. I will see what is what the next time I get around the car. Thanks a lot, Tony.

Shogun..
i have similiar issue i get heat on passenger side and rear seat but not driver side.
i have a 96 740 il.. so far with radiator, thermastat water pump replaced and most hoses.

1996 is an E38, that is not my speciality, I just know the E32.
For that better make a new thread. I assume that in your case also the heater valve on one side might be stuck. But the control module is completely different from the smple one in the E32.
But basically you can check the functions as described above for the E32.
On the E38 you have the advantage that with a good diagnosis tool you can get much more information out of the system than with the older E32 model.
E32 is quite limited with online diagnosis. Depends also on the built year even on the E32. For example the Peake tester can get out of my 1988 model only about 20 fault codes, that's all.

i have similiar issue i get heat on passenger side and rear seat but not driver side.
i have a 96 740 il.. so far with radiator, thermastat water pump replaced and most hoses.

http://forums.bimmerforums.com/forum/showthread.php?t=892984

http://forums.bimmerforums.com/forum/showthread.php?t=892984


B child .. thanks for the info.. i just need to find out where it is on my car.. toward the rear of the motor if you are looking at it is what it looks like.. close the firewall?

B child .. thanks for the info.. i just need to find out where it is on my car.. toward the rear of the motor if you are looking at it is what it looks like.. close the firewall?

Spot on - if you have a 740 ;)