I recently had an air con failure, no cool air, after diagnosis it turned out to be a compressor failure. The symptoms were there for a few weeks but I ignored them thinking it was my imagination. The main symptom was the engine speed dropping about 100rpm when the car was at stand still ticking over and the compressor started, this was not present before. The next symptom was loss of cold air during a long run, I switched off the compressor and let it cool down, the cold air returned after about 10 minutes, the following few days all was good. I parked up the car for a week and upon starting it there was no cool air. After being advised by a colleague I took the car to Rasa Sayang at SS14 (Guan), he diagnosed the failed compressor, recommended that the condenser was changed and advised that a new drive belt to be fitted. All fixed in 3 1/2 hours at a price much less than I was quoted by a local branch of a tyre dealer. If you want Guan's contact please PM me.