Audi Repair: A/C Not Working, climate control system, audi a4 v6

Question
I have a 1998 Audi A4 v6 Quatrro.  About one month ago I was driving on hot day - about 101 degrees.  I came to a red light, my idle began to decrease, and the car eventually stalled.  After the car stalled, I could not turn it over.  All I heard was a rattling sound coming from the engine.  I thought the worse.  However, I turned off everything that drained the battery - including the A/C. ( I thought it might be the alternator)  After doing this, the car started - no problems.  However, I did not have A/C.  I can turn the climate control system to manual and it blows air, however not cold.
I next searched audiworld forums and found codes for the climate control.  I discovered that my outdoor air temperature (G89 - above the glove box, below the air pollen filter) was faulty.  I was receving a code of 4.1 and 18.3.  I replaced the temp sensor.  HOwever, the A/C is still not working.  IS there anyway I can test the compressor to rule that out as a problem?  I read in the Bentley that I can jump the compressor via the high pressure switch.  IS this the way?  Also - I have checked the refridgerant level.  It was excessively high, I cleared the system and placed the right amount in.  This did not cause the compressor to engage either. Any help would be greatly appreciated.

Answer
HI
The way I will do is:
I will check for power at compressor ( there has to be 12v)when A/C ON
If the clutch does not comes ON and there is 12V - the clutch is bad. If it works you will need A/C gauges to see HI and LOW side press. if there is no press. the compressor is bad.
good luck                   pltech