Here is my problem, I run my A/c and it turns off instantly. I took it to my trusted local A/C guy and he discharged it and recharges it. And it holds pressure etc. But when you turn on the A/C the pressure shoots up to 400 psi and the cut off switch turns off the compressor. He eplained to me that something was preventing the cooling fan from turning on. So I called Audi and they said that if I have power at the fans then it was the fan module, so I spent $160 and put in the new module. And I turn on the A/C and still no fan. (side note) both fans will turn on when the car gets over the 1/2 way mark on the gauge inside the car. So I know the fans work.

Is there some relay or sensor that controls the A/C turning on cooling fan?

Thanks in advance for helping out !!!!

 

there definetly is a relay that would control the fan that gets a signal from the a/c unit

 

after alot of research and using a friend's alldata software I found out that on this car that the switch that tells the fan module to send the power to the fan is inside the high/low pressure switch. It has 4 prongs on it and when 3 & 4 close by noticing the pressure rise it turns on the fan thus solving the problem. Not bad for $310 total including my A/C guys hour of labor to have my A/C back.