My 97 A6 Quattro's climate control has taken over, not unlike HAL in 2001: A Space Odyssey.

I've spent the afternoon reading posts, and I can't find anything quite like this.

The climate control stops and starts on its own. The display goes dark, and it comes on and off, every minute or two the blower goes high. Hit a button, you get the display and can sometimes adjust temperature or fan; when you let off the button, it goes dark again and continues its own behavior.

If I put VAG-COM on it, it stabilizes, sometimes working normally again for up to 20 minutes, and then it resumes the erratic behavior.

Any insight would be greatly appreciated.

 

I have a 1998 A6, so may not be the same, but I had a problem with the climate control system. I can't say it went haywire, but it did act odd. Would hold fan speed then go up to full. Could change temps, but system would reset or shut off after a few minutes. Turned out to the the blower control module. Mine was behind the glove box, not hard to get to. I might have put some picutres on my profile. Dealer wanted over 400, found online for around $80. Sometimes when looking at the old one you can see a charred plug. Also may be best to pull out to confirm exact one used, then order part.

 

Thanks for your reply.

I've been reading a bit and wonder if this is sometimes referred to as the relay? One place said it was attached to the blower fan.

Any further info would be greatly appreciated.

 

I have a few pictures in my album. Its not a 97, but you can look for it behind the glove box, might be in the same spot. You might see a charred connector and that would tell you it is bad. Also best to pull it out as to make sure you order the exact same kind.

 

Thanks for getting back to me Euge.

Since the last activity, I found that the resistor, which is the same as the control module, is under the hood. I removed the cowl between the wipers and the firewall and found the blower motor and towards the right side, the resistor. I replaced it with an eBay find, but absolutely no change in behavior.

I think the next thing I'm going to try is removing the climate control unit and sniff around to see if I can smell anything burnt, look for anything amiss, and also clean all contacts.

If I unplug the negative terminal, it works ok for a bit but then reverts, so I fear the problem is in the computer. I wonder if anyone has any insight on whether this may be the nightmare I think it is (or not).

 

I recall there are some companies that will rebuild/repair the climate control unit. You might contact them and tell see if they think you should send it to them. One I found was autoecu d_o_t c 0...m. I saw some posts about disconnecting the battery for 30 minutes to reset computer. Did you try that.

 

I did remove the negative cable for several hours, but nothing. The only thing left is the control unit or the main computer (Is there a 'main' computer?). I will pull it soon.

Thanks for the suggestion on the rebuild company. That feels like the next option.

Thanks for getting back with me.

 

Problem solved. I'd used BBA-Reman before, and checked their site. Lo and behold, there was the HVAC control head for my car, and their description of what they fix on this part was precisely the symptoms we'd been experiencing.

Purchased the service on ebay Sunday ($89), received the shipping label Monday, sent same day, arrived Wednesday 9 AM, repaired and sent back out by 11 AM, in the car functioning properly Friday.

A happy ending... thanks Euge, and BBA-Reman is great.

BBA reman. ABS, ecu's, throttle bodies, air mass meters, and catalytic converters