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      11-20-2010, 10:15 AM   #5
wildag
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Drives: '06 ///M Roadster
Join Date: Aug 2009
Location: Reston, VA

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Quote:
Originally Posted by FerRrari View Post
Has anyone experienced their A/C only blowing really hot air even if the temp is set all the way to cold? It has happened twice with my Roadster but it goes away after a while so the dealer cannot reproduce the issue.
I had the exact same issue. Took my car to the dealer several times when the issue reared its ugly head, but of course they were always busy with no immediate availability. And when I took the car back, they couldn't reproduce the issue, even though the service advisor had seen it in person several times.

In the process of taking "pot shot" attempts at fixing this problem, they replaced the IHK module and down graded the firmware on that module. That didn't have any affect on the problem.

They finally fixed the issue by replacing the stepper motors that control the air vent flaps under the dash. They found that the passenger side foot well flapper motor was completely worn and shorted. The problem has not returned since.

The explanation of the problem is pretty straight forward. When the the IHK (A/C module) detects that its unable to control any one part of the A/C system, it goes into a "safety mode". The safety mode is hot air only, with all possible flaps pushing air to the windshield, and manual control of the fan. This ensures that you can drive the car in icy conditions.

What I deduced after having the issue fixed is that in fact, its very easy for a technician to find the logs of this occurring in the IHK. But because the techs either don't know about it, or are too lazy to try it, the simple diagnosis is done.

I've read of several others on other forums having this problem, and at least two of those were also fixed by replacing the passenger side foot well vent flap motor.

I believe the part they replaced was number 3 in the following diagram.

http://www.realoem.com/bmw/showparts...81&hg=64&fg=45

Last edited by wildag; 11-20-2010 at 10:24 AM..
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