Recently I faced a strange and unique problem with my car AC.
IT seems to be working fine when at speed, but when I got stuck in traffic jams or at traffic signal or if the car is just idle, the AC would stop working and would blow warm / normal air and not chilled air. Also, I noticed that the RPM would start to increase it self.
I took it to the AC tehnician and he said that it was related to AC service, and I should have the car ac serviced, which I did.
Even after ac service the problem remained there. I visited him again, and he told me that I should visit him as and when the problem occurs.
I then visited him as and when the error occured. On inspecting further, he told me that it is related to some MAGNET under the compressor of the AC. So when the magnet heats up , it stops working and which in turn causes the compressor to stop working.
So I had that MAGENT repaired and the AC seems to be working fine.
So next time when your car AC stops working, may be its not the time to service the AC but to have its magent checked.