So, to follow up on my rather unintelligable Saturday cocktail soaked post with a Sunday morning ask a darn question please post:

What sensors control the compressor clutch on my 01, A6, Quatro and where are they? Interestingly the A/C blows hot when the outside temp sensor spikes over 100 degrees. There's plenty of cold when it works.

Thanks for your patience.

Ray.

 

Lots of things actually, the outside temperature sensor can inhibit the A/C compressor clutch from working if its malfunctioning, the A/C pressure cycling switch on the side of the condenser, and the A/C control head itself.

My best guess is the system is overcharged so when the temperature is really hot outside, the a/c pressure cycling switch turns off the a/c because the pressures are too high. Thats just speculation though. Have you checked the fault codes in the A/C control head with your vag com yet?

 

Thanks very much. Your comments show great wisdom. I will release some refrigerant and investigate the external temp sensor. by the way, where is it?

Ray.

 

The external temp sensor is located right behind the bumper and right in front of the radiator. You should be able to access it without taking off the bumper, sometimes you have to remove the grilles in the bumper to get at it. However you don't know what you're dealing with so before you go and start releasing refrigerant (not legal BTW) you need to have someone check the system with a set of manifold gauges, then have the fault codes checked the A/C electronics. You can also monitor the exterior temp sensor with the vag com, if its going all over the place, and sometimes dips below 50 degrees it will shut off the A/C compressor. The pressure cycling switch is much more likely in this case, but the first thing you should do is have the pressures checked, and fault codes retrieved.

 

Thanks very much for your help. I'll get the pressures checked by someone with the propper equipment and will be able to know if they are trying to skin me for a new part that I don't need.

Ray.