A few months ago I got in my car in the morning and the a/c wasn't cooling. Since then it cools maybe 5% of the time. The fan still blows and freon is still in the system. Compressor doesnt even engage for a second. When pressing the cooling button on the dash the engine tone changes but the compressor doesnt enguage.

The relay and 10 amp fuse in the engine compartment is good. I replaced the pressure sensor by the compressor with a used known working one.

I borrowed hpt and attempted to turn on the compressor with it but it didnt work. Most likely it is cause that feature doesnt work on the cobalt. There are also no engine codes

Anyone have a trouble shooting diagram. I have access to a electrical tester.




I have searched on here and found that a few people had a problem with the pressure sensor but that doesnt seem to be the case with me.

 

Try jumping across the compessor clutch itself. Supply 12v power to one of the terminals on the clutch, it will engage if it's working.

 

sweet! no ac means you must be on GM stg3

 

check the harness end of the connector for the compressor for 12 volts. if you have 12 volts there and the compressor is not turning on, you more than likely have a bad compressor clutch

 

tested the voltage for the plug going to the compressor. it was reading 13-14v when a/c on and 0 when off. So the compressor is bad. Sucks cause I used my a/c less than 50% of the time.

Joe most likely has one for me.