yact: air conditioning pressure switch?

[klod]

97 Plymouth Grand Voyager, the a/c will cycle as usual, and then at some point (minutes or hours after I first start the a/c) it will cycle off and will not cycle back on unless I manually turn it off and then back on. I tried to do some research, and it sounds like a pressure switch is bad. Where are the high and low pressure switches located? Is it something I can test and/or replace? Thanks.

 

[Pepsi90919]

it's a chrysler, so... drive it into a lake and your problem is solved. :beer:

 

[klod]

Originally posted by: Pepsi90919
it's a chrysler, so... drive it into a lake and your problem is solved. :beer:

Hmm, 132,000 miles and this is the first real hiccup. I'd like to keep her for a while longer. Anyone else?

 

[Quixfire]

What do you mean by "manually turn it off and then back on?"

 

[klod]

Ok, say I'm driving with the a/c on, and cold air is blowing out of the vents. At some point I can feel the air start to warm up and it feels/smells humid, like the vent is on but not the compressor. I reach down and hit the button to turn the compressor off, leaving the fan still running, wait a second or two, and turn it back on. I feel the compressor grab and cold air starts blowing again. It doesn't seem to happen in stop and go driving, but on the highway at steady speeds. And sometimes it will work fine for hours, other times I'm turning it on/off/on every five minutes.

 

[Quixfire]

OK, it could be two things.

First, an bad A/C relay, turning the switch on and off will reset it.

Second, coolant or a/c fan isn't working and you high side pressure get over the limt and disengages the compressor.

I hope this helps.

 

[klod]

Where are the high and low pressure switches located? Is it something I can test and/or replace? Thanks.

 

[Quixfire]

The low pressure switch is on the expansion valve near the bulkhead and the high pressure switch is on the compressor. The only test I've ever done was to bypass them to see if they were the fault.

 

[klod]

Thanks Quixfire. I assume replacing them would involve evacuating the system?

 

[IGBT]

Need to put some gages on it and check the op.pressures. May be overserviced with too much freon..was it worked on lately?? Get the shop manual.

 

[klod]

Originally posted by: IGBT
Need to put some gages on it and check the op.pressures. May be overserviced with too much freon..was it worked on lately?? Get the shop manual.

It's done this for the last couple of years. In March I had a truck back into the front end. The condenser was replaced, so I know it was purged and re-filled. No difference in this problem, it's still cutting out.

 

[Quixfire]

Originally posted by: klod
Thanks Quixfire. I assume replacing them would involve evacuating the system?

On your car it does. But I would let a professional mechanic look at the system, I still think it's related to my orginal post on your concern.

If you lived near me I would be happy to check out for a small fee. 😀

 

[Evadman]

Originally posted by: Quixfire

Originally posted by: klod
Thanks Quixfire. I assume replacing them would involve evacuating the system?

On your car it does. But I would let a professional mechanic look at the system, I still think it's related to my orginal post on your concern.

If you lived near me I would be happy to check out for a small fee. 😀

Probably the same fee as mine. A case of Beer 😛

 

[klod]

Originally posted by: Quixfire

Originally posted by: klod
Thanks Quixfire. I assume replacing them would involve evacuating the system?

On your car it does. But I would let a professional mechanic look at the system, I still think it's related to my orginal post on your concern.

If you lived near me I would be happy to check out for a small fee. 😀

I wouldn't mind letting a "professional" mechanic look at it. I just don't know any around here. If it's the relay, is THAT something I could replace myself? Where is it located?

Sorry for the questions, but I don't want to get gouged at a local shop. I just need someone to point me in the right direction. Thanks.