mcholdfast

It's an 88 S4. We have no power at all to the A/C control head or the switch panel directly below it in the console. We've had pretty much everything off of this car to either replace or clean so anything is possible.
What is the power source for terminal 86 on the fan blower relay. Wally says it comes from the ignition switch but is there a connection somewhere in between that we may have left loose? Where do we begin?

Dan87951

Subscribe! My dad is having a similar problem with his. He said while he was driving the interior temp sensor (right to center vents) was glowing red and a puff smoke came out and everything died. By chance did this happen to you as well? I haven't had a chance to troubleshoot but will be down there today for father's day weekend.

mcholdfast

No, different situation here. This one was working before we took everything apart to replace the dash, clean the CE panel, replace the vacuum pods, etc. etc. etc.
We are getting ready to try a third A/C control head. We had a spare but not sure if it is good so I'm pulling another that's known to be good. Will report back soon.

mcholdfast

Third known good A/C control head made no difference. Still no power. We'll keep searching. Any suggestions appreciated.

mcholdfast

We figured it out about an our or so after the previous post. I'll let this post simmer for a while and see if anyone guesses what the problem was.

mcholdfast

No input so I'll spill the beans.
When you disassemble the dash and console of an 88 S4, be careful. There are two 6 pin wire connectors near the console that can easily be swapped. This will result in no power to the A/C head unit or switch panel below.

fraggle

Ooo bet I did that one, then ohmed out and tested bloody everything, found no problems but a blown 7A fuse, buttoned it all up and it worked fine.