I hope this post will help a few people with air con problems, my car has done 143000 miles with no issues till we have a really hot summer, the evaporator fan (electric fan) decided to fail while on holiday. Not a big problem till standing in traffic, then air con blows warm till you move off again. As air con is mostly used while moving slowly it became a problem. After about a week on school run about 6 miles a day air con failed.After putting vcds(full version)on car no faults found expect electric fan inop.
After repairs to fan, clean and test on bench all sorted. The fan is fairly easy to remove without stripping car down, takes about 20 mins. biggest problem is the route of the wiring around radiator.
still no air con and no shown faults.
I read a few post which suggested poss low pressure in system or g65 sensor as I could only check pressure on vcds, took car to kwik fit as they don't charge if they dont fix!!!!
re-gas still no air con, as word of warning you get what you pay for at kwik fit be aware.
re-tested system on vcds pressure was even lower now than before, as system seems to need between 5 and 6 bar to activate now only got 4.2 bar after kwik fit re-gas now things going down hill fast.
After further electrical testing found G65 sensor was now faulty not sure why but seem to giving incorrect reading, fitted new sensor pressure back to 5 bar.
As car was having new front tyres fitted by local ATS had a chat with there air con guy about the probs I have had so we spent a hour or so testing with vcds running on car and doing a re -gas. we found we had to clean system twice. so no air,
At this point thinking Audi dealer visit on cards after trying to book car in, answer no slots for two weeks, service advisor spoke to senior tech, who rang me back and gave me a few pointers as most of these already had check, suggest one thing that seems to be a problem on the avf engine if fitted to vw or audi the cuss drive fails.
On this type of air con pump part no. 4B0 260 805M made by denso has no electro-mag clutch has a rubber coupler instead.
after stripping car found to be the prob has mine was totally gone. I this was the prob. System also starts to become less efficient as well before failure, this could also be a problem, DENSO don't supply parts only new compressors through normal outlets around £300. But audi do a replacement pulley kit part no. 4B0 260 210 NOT CHEAP, but cheaper than new compressor and re-gas. Fitted today with no real problems compressor doesn't need to come of car just lowered down to help access.After road test and ice cold air-con found all ok. Also engine a lot quieter around drive belt area as this has always been fairly loud.As I changed alternator clutch and belt last year due to belt slip thought all was ok.
I hope this helps people with the similar problems please feel free to ask any questions I will try and help.