Hi Group,
The air conditioner in my son’s 2002 Monte Carlo SS is blowing hot air. (The air conditioner air does t get cool at all) We noticed that the condenser never kicks on when the A/C is activated. Does anyone have a good troubleshooting guide for ACs, or anything that can help me figure out where to start? I am looking at the fuses - however if there isn’t anything obvious with the fuse situation- I quickly run out of ideas.

Thank You,
Randall

 

Very doubtful it will be the fuse, that's fairly rare. Frankly, even if the fuse is bad just sticking another in will rarely fix the problem as something caused the circuit to over draw in the first place - so additional diagnostic would be needed anyways.

More commonly, especially on a car that old, is refrigerant charge. If pressure is too high (from someone who didn't know what they were doing putting too much in during a refill/ top off) or low (from leakage), the computer won't command the compressor to run to keep it from getting damaged. Thats always my first step when diagnosing AC issues - hook up gauges to the high / low ports and see what the actual pressures are relative to spec.

If pressures are good, but its still not coming on, my step 2 is to check voltage at the terminal on the compressor. If pressures are good, then you can see if the plug has power (clutch failure - its getting power but not engaging) or none (something wrong upstream with the electronics as nothing is sending the signal to engage).

In my limited experience, between low charge + bad clutch/compressor that covers the vast majority of failure cases.