I have a 1996 Blazer I am in need of some General AC info. My boyfriend is a good mechanic but we cant figure out what pressure switch is where on the AC unit. I have been reading that the Low pressure switch is on the accumulator but i was told by the guy at the parts store (i know not many of them are too bright) that they are only located on the compressor. So I guess what my question is is where are all the pressure switches for the AC unit and are they a high or low? I need to replace it/them.

 

Why do you need to replace the switches?

The Low pressure switch is located on the accumilator. The high pressure switch is located on the back of the compressor.

You can replace the low pressure switch without blowing the charge. Unfortunately the same cannot be said for the high pressure switch.

 

because thats what we figure is wrong with it. when hooked to a battery all works great. was told by numorous people thats what wrong with it.

 

There is a possibility that both switches fail but I would bet against it.

If the pressure in the AC system is below a certian pressure the low pressure switch prevents the compressor from coming on. If it is too high, the high pressure switch shuts the compressor off.

It would be in your best interest to use a meter to see which switch is open. That way you (A) dont buy something you dont need. (B) can determine if the switch is actually bad or not.

There is the chance that both switches are working properly and that the system pressure is actually too low. Forcing the system to run with too little refrigerant in it will kill the compressor. PLEASE dont allow someone to talk you into running the ac with the switches jumpered out. They are there to allow the system work correctly and protect you and your vehicle. (Besides, do you really thing GM would install anything that you didnt need?)

Good luck!

 

Is it the original compressor? If so it was built for to R-12 antifreeze, which is now illegal cause of some loud mouth environmentalist trying to fix a problem that he can't prevent. You may have to get the 134a converter kit for it, but check the switches first it may just be them.

 

It is R134a compatable it says on the compressor to use it. As for the switches we think it is one of them that is out but we don't know which one. We have put freon in it and the pressure was perfect. We did that about a week ago which is what led us to the pressure switches. Thanks for the help guys! I will keep you posted on if the problem is resolved.

 

Oh ya and the hooking it up to the battery was just to test the compressor. I would never leave it like that.

 

Well that wasn't it. I guess I will just take it to an AC Guy and see what he says. I will keep ya posted.

 

The refrigerant you put in may have leaked out. If you had to put refrigerant in it to get it to cool, then there is a leak. The big question is.....How big is the leak? It can take years, months, days or minutes for the froen to leak out. If the leak is large enough to leak out in a week, replacing the switch may not allow the system to work either.

The pressure switches can be tested with a multimeter. (You can buy a multimeter for less than the cost of a new switch.)

Troubleshoot the problem (Cheap), dont guess and go buy parts. (Expensive)

Sorry my post didnt flow well. I work mids and it really is goofing with me.

BTW - Thank you for having the good sense not to try to run the system without the switches!

 

We are going to check the wiring to see if there is a loose one. The high pressure switch did need to be replaced. There was a prong missing. We got an automated thing that yells us how much feon is in there and that was good earlier and we will check the levels tomorrow to see if its leaking. The problem is the clutch wont engage. That's why we did the battery test. The clutch is good we just gotta figure out why it wont engage that's what led us to possibly a wire issue. Will keep you posted.