For those who on their aircon, usually will have a "thun" sound coming from compressor in normal working conditions.
So for those who on their aircon but did not heard this sound, most likely is the compressor got shorted.
I got this problem when travelling from one area to another area and the aircon was working fine, park there for a few hours and start engine hot air blowing out again. Did not heard the sound. After diagnose at one of the WS, found that is compressor problem.
The person just use a tester to test on the fuse and the fuse was open. He inform just change 1 of the part in compressor (repair) and top up gas. Now working fine.
Meaning to say, actually no need to change out the compressor which I did about 3 years back. Just change one part inside compressor ok liao.