my a/c is acting up, it runs cold for a while and then it will blow just air kinda muggy. the compressor starts and a/c fan all going at the same time when stopped, but then the compressor turns off and so does the fan. it'll start up some times, and others times it'll just blow muggy air. any ideas?

 

could be just a loose sensor or grounding wire loose...... need to be vagged for code.....

 

Does this happen at idle?? If so mine does the same but mine doesnt do that when I am on the freeway!

 

in idle it does the same, turns on for a while and then off, sometimes it just stays on for a long period of time.

 

my guess, might just be low on freon...just remember, too much freon makes it do the same thing, and don't buy that fix a leak stuff at the auto parts stores, it will damage a mechanics a/c machine if and when you decide to take it in to get it fixed...I think it's just low on freon personally...I'd have it tested though with a good audior A/C shop....

 

Good on freon, took it to mechanic and they checked the freon, all good. It seems that the compressor loses power completely. Checked electrical current and no power was getting to it, but then it'll turn on all of a sudden. Mechanic need the a/c electrical scheme, to find the source of the problem.

 

Its possible it is your A/C relay.

 

are those the one's located in the bottom of drivers dashboard?

 

Here's a pdf from bentley publishers for a b6 A4, might help though....

http://www.bentleypublishers.com/ima...i.b6.wd.02.pdf

 

It's kind of hard to see, but here is the simple a4 A/C wiring diagram...