A/C Compressor

Good day. I just got my 2000 Impala A/C pressured up and the clutch is not engaging on the Compressor. Theres 70 PSI in the system, but it still won't activate the Compressor clutch. Turned the fan up on full, set the vent properly, pressed the A/C switch. How can i check the clutch for operation?

Thanks, Kev

First check to see if you have power and ground at the clutch coil wire connector. If you do and there is a good connection then the coil is bad. If there is no ground, repair it. If there is no power check the relay (switch it with the one next to it).If this is alright then you need to check the switches and wiring between switches , relay and ECM. you will need a pin-out or diagram to do this. Also, some GM vehicles require that the ECM be reset if the A/C pressure has gone too low, I do not know if this is one of those but it is always worth a try. Let us know what you find.

70 psi in the lo or high side? What do you mean you got the ac" pressured up"?

Just that he checked the system for leaks, and before i left he told me that there is 70 PSI pressure in the system, but the Compressor clutch still wasn't kicking in to activate the Air Conditioning. There wasn't any drop in pressure. I did turn off the ignition and turn the outer pulley by hand, and it turned without much effort.The main pulley(The belt spins) turns very easily. Not sure what you mean, Low, or High side. He did say that the pressure equalized on both sides.

If the system does not operate how could he check the pressures? Was this an ac tech? If you suspect a relay swap with another one from the relay panel that has the same id number, but there are a lot of unanswered issues that make it impossible to give you any meaningful help.

Sorry, but i don't know anything about Air Conditioning Systems. Only what other people say, or tell me, or what i read in the Haynes Repair Manual. He is a Refridgeration Tech. The person in question.There was no pressure in the system in the first place, because the day before i had an auto mechanic remove the old compressor and install another one,which was very noisey and was throwing out metal particles. He only built up pressure in the system to check for leaks, and to see if the pressure would hold,which it did, but for some reason, or reasons the pressure would not activate the pressure switch. He said to me that it should have. I have an appointment to put the car in a shop for diagnoisis and repair on Wednesday.

Then that is path to take, hopefully system is not contaminated from debris deposited as a result of the compressor failure.

Thanks Maxwedge for the info and advice. I'm praying that the trouble will be finally solved after a visit to the Dealership. It's gonna be interesting what they say there on Wednesday. I'll let the group in on the final decision afterwards.

Well! Had the car at the Chevrolet Dealership today, and told them that the Compressor wasn't engaging when i activated the A/C. Cost me $114 & change for them to tell me what i already knew. They are suppose to be the experts. No suggestions as to what i would be better off doing to get the Air conditioning working again from any of the mechanics there. Gladly took my money though.

So what was there actual diagnosis for 114.00, what did they say was necessary to fix it?

Welcome to AF, you have tagged onto to an unrelated thread for Impalas, this is going to the Malibu forum.

They told me that there was voltage on the compressor plug,and that the fuse and relay were ok, but the compressor clutch would not engage. They then backed the car out of the garage. They didn't tell me what needed to be done to get the Air Conditioning working. I assume that from that i,ll need a brand new Compressor assembly. $411 plus Freon plus Labour plus 13% taxes on top of all that.

I would insist on an accurate recommnndation or diagnosis from them that agrees with your assumption before just replacing the compressor. BTW the clutch coil could be bad if that is there diagnosis and not need the whole compressor.

After calling the GM Headquaters and complaining about the service i got at the local GM dealership here, they finally told me that the coil was bad in the compressor unit. They said it would take about three hours to replace the coil. Went on further to say that i would be better off buying a new complete compressor. At least now i know what i need to repair it.

Thanks people for all your advice and input.
Best regards, Kev

After calling the GM Headquaters and complaining about the service i got at the local GM dealership here, they finally told me that the coil was bad in the compressor unit. They said it would take about three hours to replace the coil. Went on further to say that i would be better off buying a new complete compressor. At least now i know what i need to repair it.

Thanks people for all your advice and input.
Best regards, Kev


the compressor clutch coil may be bad or possibly it is the connector at the compressor that has a bad wiring connection....the coils are very durable but the connector wires to coil are a weak point....also if you had the proper amount of refrigerant in you a/c system at rest no compressor running the pressures should be around 110psi.....70 psi means you have no liquid in the a/c system ..they may have added just vapor to your system to test for leaks....


if a dealer does this they will be looking for 900.oo......your vehicle is too old to have dealer repairs on this type of item ...they will steer you to get a new vehicle and they use high repair charges to convince you of this..

I've decided that the car is just not worth the cost and expense of buying a new compressor, Orifice tube and Accumulator, not to mention recharging the system and Labor charges. Nope. Just not worth it anymore. They claim thy did put the proper amount of refrigerant in though. Thanks for all your advice and tips. This is a very informative forum. I'll be referring to it in the future should i need any questions answered. Thanks again.