I have a 2007 HHR with A/C problems. The radiator was changed after front end damage. The system was left open for a couple days and was not vacuum-pulled before recharging. The A/C works for 2 weeks then the compressor will not engage. Now, the system is recharged, but the compressor will not engage unless you use a jumper wire. With the jumper wire, the compressor engages and the system cools but compressor does not continue running when the jumper wire is removed. I was told that I should change the low pressure swith. I traced the lines and was not able to locate any switch on the low pressure side. I did find the high pressure switch near the compressor. Is there a low pressure switch on this system and where would it be?

 

There is only one pressure switch and you have found it.

 

You sure it's the high pressure switch you'rre lookin' at....sounds like low pressure to me....and if you're pokin' it in the eyes and the compressor starts up I'd think.....low on charge? Have you put gauges to it?

 

I seem to recall GM having trouble with the low pressure switches in the past. They used to put them on the receiver-dryer. Some compressors have a high temperature switch on the compressor.

Why didn't they vac the system down before re-charging it?

 

That was my fault. I did all of the work myself failed to vac the system. Had a local shop check it this weekend and he could not find problem. He did get the compressor to come on by poking around the wires in the area of the compressor, and it worked fine for 30 minutes or so, then kicked off anf he could not get it to kick back on. He gave up on the problem and I will pick it up up my car this afternoon(only good thing is he will not charge me anything) My next step i think is to change the switch near the compressor. I hnave never doe this. Do i have to drain the freon from the system to do this. If I do, i will definatly pull a vac before rechqarging. Any other ideas? thanks

 

Have you put gauges on..... you know....checked the at rest pressure....it should be 'bout whatever the air temp is....... letting it run was/is not the best thing to let happen if the freon quanity isn't close to correct. If I were you I'd capture the freon that's in the system, vac for 45 to 60 minutes then see if she holds vac........ if things are cool at that point, cross your finger and recharge with the correct amount....... ain't no time to be guessin'.

 

Just curious, which terminals did you jump? I see more than two when I pulled the connector. Don't want to blow up the computer.

 

If you don't know what you are doing you could hurt yourself and the car. please don't try.

The thread you are asking in has been dead for 6 years.

Maybe, start a thread of your own with the exact problem you are having. It is most likely much simpler than you think.