I have been trying to fix my A/C.. I had it recharged and it seemed to hold a charge.. I found the pressure sensorin the front of the car (under the passenger headlamp), But I can not find the other one.. Anyone have any idea???? Also, is there a way to test it?? I am just PRAYING that I do not need a new compressor.

I don't know whether your car is the same with mine or not.

The high pressure side (only used to check pressure) is located in front of the radiator.

and I don't know where is the low pressure side for sure. (to recharge, it could be the one that you said under the headlight).

From Bentley publishers, the low-pressure side is behind the firewall next to the battery (not the brake master cylinder side, the other one). I believe they have 2 sensor for the high pressure and low pressure side.

Audi has been known to have small leaks in their A/C system which is very hard to trace. The only thing you can do is to let the expert do it.

Don't take my words, below is pictures from bentley manual



Low pressure side
<img src="http://pictureposter.audiworld.com/50710/1.jpg">




high pressure side
<img src="http://pictureposter.audiworld.com/50710/2.jpg">
<img src="http://pictureposter.audiworld.com/50710/3.jpg">