Hi, I have a 1985 SS Monte Carlo. The ac fuse is good, the system is full. I get power to the low pressure switch. I have replaced switch twice thinking maybe the new one was bad. No luck in getting the ac clutch to engage. I can jump the low pressure switch wiring connector and ac clutch will engage. The parts store tells me that there is a high pressure switch somewhere but I cant find it. I only see the connector going to the ac clutch and no other electrical connectors going to the ac compressor. Can anyone give me any ideas to try?

 

here is a youtube link that may have some vids that might help you out.

 

Thanks for the reply and the video. Unfortunately, it was not any help. I am pretty familiar with the ac system I have but I am stuck. Ac fuse is good. Blower works fine. I get power to low pressure switch on receiver/dryer. I can jump the low pressure switch connector with a paper clip and get the ac clutch to engage so logic (for me) would say that the low pressure switch is bad. I have replaced the low pressure switch multiple times to ensure that I did not get a new one that was bad. It was suggested to me to (bleed) the high pressure hose fitting with small screwdriver to see if junk comes out of the receiver. The system was working fine but now...not working. Napa, autozone, advance all show a high pressure switch is associated with my year make and model but they have no information as to where it is located. There is no wiring going to the compressor other than the spade connector to the ac clutch on the front of the compressor. It has the original compressor (Harrison 434) model # 11313434 that was converted to R134a a few years back.I am unable to determine what else might be causing the ac clutch no to engage. Any help would be really great!

 

Have you checked the AC comp. clutch relay?

 

I am unaware of an actual relay. There is the spade connector in the front of the compressor that activates the ac clutch when I jump the low pressure switch connector. It also activates when I jump directly from the battery. The ac clutch is good as it will activate when power is applied directly. Please tell me the location of the relay you are referring to. Thanks!