I recently had the a/c compressor replaced. For some reason it will only engage when jumped. I was shown a way to keep it jumped but when I turn off the a/c, the compressor keeps spinning. Later that day I reset the battery. The next day I drove to work w/o running the a/c. Then around lunch time I drove it and tested without jumping and it worked correctly. BUT on the way home I had to jump it again in order for it to blow cold air. What could be causing this?

 

Usually not enough R-134A in the system, which tells the low-pressure cut out switch to cut power to the AC compressor's magnetic clutch.I will assume you dont have an A/C gauge set as most people dont, or cant find someone who does, but that would be best..Its not good to run your AC system with low refrigerant levels. You might want to by one of those cans of R-134A at the parts store and add a can to the system. Keep your clutch bypassed so it will take in the R-134A. After that it should run with the LP cut-out switch detecting a normal pressure. I am surprised that whomever did your compressor, didn't put enough refrigerant into the system and test it out before you got it back.Might want to take it back there and have them check it out. It is possible your LP- cut-out switch is bad, but the tech should have caught that.Wear eye and hand protection always when dealing with a high-pressurized system like A/C..

 

I will do just that. Thanks!!! Very informative advice.

 

Was the system properly evacuated before being filled with refrigerant?