Air Conditioning problem
2000 GMC Jimmy 6 cyl Four Wheel Drive Automatic 100000 miles
Trying to trouble shoot an intermittent problem in my air conditioner compressor clutch system. When the compressor clutch engages, the air conditioner works good, but it doesn't always engage when I turn the system on. Checked the system when it was working and it showed good pressures. It does this no matter which of the air conditioner levels I select on the dash switch. One day it will work the next it won't. Sometimes it will work a few cycles then quit. Wondering if there was a way to test the switch or possible a relay to isolate the problem? Or is there something else that could be the problem?
Faulty low pressure cutout switch. This switch prevents the compressor from running if the refrigerant level is low. If the cutout switch is not reading correctly, it can prevent the compressor from coming on.
Faulty compressor clutch. The magnetic clutch on the compressor requires full battery voltage to engage. If the voltage to the clutch is low, or the clutch coils have too much resistance, or the air gap in the clutch is too great, the clutch may not engage to drive the compressor.
Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.
Faulty A/C control switch. The switch may be worn and not making good contact when it is turned on.