Automatic Air Condition Control Unit Dead (No Power, No Lights) Please help

[Akhil]

Hi All,
I had a strange problem last week on my 2002 530i ( Jan 2001 production date). I gave my car for service to an Indy show. They did lot of work, most of them were like engine leaks or suspensions related (nothing A/C related and nothing electrical) except one, that it had broken fog light on passenger side and ambient temp sensor was hanging and I asked him to fix fog like and attach all plastic fixture around it, so that ambient temp sensor could be put at right place as its suppose to be. He did all works really good and I am happy with all works. But when I picked up my car last Friday, my A/C was working and for few minutes. But suddenly I noticed that, the light on A/C control unit flickered for few minutes and then completely went OFF, on dash blower started to run at full speed. When I turned off engine and took the key out, blower was still running at full speed. Now I have No power (No light, No display) on control unit, blower running at full speed. So I have no way to turn off blower or try to do any heat/cold controls. Then I called that Indy shop, he tried to do troubleshooting on phone and asked to take fuse number 9, and that stopped the blower. I took my car to him next day. He checked it up and said he will try to replace final stage unit and see if that was the problem, but came back 30-40 min later said FSU was not the problem and my control unit is gone and I will need new control unit ($600+) and gave me estimate about $750 for parts +labor + tax for replacing control unit. I live in Houston (it’s very hot in summer here) and summer is approaching, so I have no choice but get it fixed before summer starts. But I was not convinced by him about control unit going bad in few minutes, because it went off after flickering for few min, so I am suspecting, it might be a loose connection or something else. So, before spending $750, I want to take opinion from you all BMW experts here, if anybody has similar experience and it turned out to be not bad control unit and something minor and inexpensive fix. I am sure that Indy show did not test the control unit (because he might not have all BMW testing tool) and just guessing it.
I would really appreciate all your helps and expert advice what I should do next.
Thanks you all in advance.
Akhil

[Akhil]

Ding Ding, No reply yet

[Ross]

Search E39 forums(this one very heavily E34 biased) for repairs to the module.
A lot of the expensive modules are easily repairable with simple fixes such as reflowing solder joints or replacing a component ot two.
Oh, your indy is definately guessing.

[Akhil]

Thanks a lot Ross. I will search for E39 forum and post it there.

Thanks

[shogun]

http://forums.bimmerforums.com/forum...play.php?f=202
http://www.bimmerboard.com/forums/e39/