In the process of troubleshooting my 1996 Buick Regal's A/C compressor problem. Clutch will not engage. If I jumper the + wire to the battery the clutch will engage - A/C doesn't feel like it gets cold but I can't really check as I have to hold the jumper wire on the battery then let it go and run to the interior to check.

Anyways, question: Could I have a bad low pressure cutoff switch if the compressor clutch engages when I use a jumper wire? I don't exactly know how the cutoff switch works, so I don't know if it shuts the compressor down altogether or if it just blocks power on some relay along the way.

Any help, insight, or ESPECIALLY a wiring diagram for this would really be helpful. Thanks in advance.

 

Theres a low pressure switch that cuts the clutch from engaging so that you dont eat up your compressor. Have you put a gauge on the system to see where the charge is at? It may be as simple as a leak somewhere and your system is on strike. I cant recall where its located on your car but should be around the dryer area. Just take a paperclip and disconnect the plug and jump it while the ac control is on. If the system kicks on then your charge is gone and the shitty process of tracking down a leak begins...

 

Your Regal "W" car has a variable stroke V-5 compressor-- no pressure switch and no need to "jump it" merely pull your vacuum and charge into the vacuum - when system pressure hit 47 psi the ECM will turn on th ecompressor- the 3 -wire transducer on the high side is what tell the ECM to turn on compressor and turn on cooling fan(s) and to turn off compressor if pressur eis too high-- if system is "dead flat" you have a pretty big leak-- need to find and fix leak first- then evacuate and recharge-- most likely leak location is compressor shaft seal- look for oil sling around front of compressor and anything near it....

Also- never try to "jumper" a 3-wire transducer- it can damge the ECM....

Your system will take 2.2lbs/36oz

 

Good deal, thanks for the insight, guys. I hadn't even tried screwing with the 3-wire part, I simply jumped 12v battery power directly to the compressor and it kicked on.

 

If you have a vacuum pump pull vacuum and shoot gas.Go to Walmart and buy Artic freeze 134a. If not shoot gas bleed and shoot more( I never said this)

 

I already busted out 2 cans of R134a (24oz total) and an 8oz can of the leak stop+dye into the lowside. Gotta put a gauge on it, but I didn't see any major leaks that were easily visable, although I didn't look all that good yet. But even after that, the compressor wouldn't kick on. Only way it kicks on is if I throw a jumper the battery to its + side wire(green wire).

Shoot gas? With the understanding that you never said that, any more insight on it? I'm assumming to kill any moisture or something?

 

Yes to purge system and remove moisture. With the compressor running with the jumper and gas in system did you get cool air? Did condensor fan come on?

 

Hmm, I don't think this one has a vacuum pump, no lines to just pour it into that I can see. Forgive my ignorance as to how it all works, but is there vacuum on the lowside when the compressor is running, or just lower pressure? Thinking on sticking on side of the fill line into a gas can and the other on the lowside port.

 

No Im talking about A/C tools. When you charge and recharge you want to evacuate the system. You have to have a portable pump to pull vacuum on the system. It also removes moisture. If you pull vacuum and let sit you can watch gauge and determine if you have a leak before you inject the costly gas. It also will let you inject gas to a dead system as it is under vacuum. If you cant get it going hit me on a PM and I will put you in contact with a fellow TR member who does this daily and has all the equiptment and it will be on the low.