I have 93 C4

Has anyone changed out the digital A/C control head?

I'm chasing an ac issue. I just figured it was the compressor, but after getting the wiring diagram I started to see my I was getting no power to the compressor ( when using power probe and giving power directly to compressor it came on, blew colllllld air and had no leaks!!!).

Sooo there are two relays on the passenger back wall underneath the coolant tank... Not getting power to the relay from computer that gives power to pressure switch that gives power to compressor ( I think that's how it went) giving power to the blue wire, I think, gave power to compressor. So I took a small piece of wire and connected two wires that made power to compressor (in the relay ) It seemed fine..It idled for 10 minutes great blowing colllld air ...drove it for aboukt .2 miles and the car felt funny... Almost like a big drag i dunno.. But all i wanted to do is test that the air worked..

How would i know if compressor is sbout to lock up?

All the controls inside work.. Fan speed, temp, air direction etc... Could all the functions on the control head work but give no power to anything.

The heat works perfect..

I know squat about ac, I'm just trying to figure this out...


Thanks

 

Low Pressure Switch opens ground to the Relay - check it to make sure the contacts are closed. If not, it's out of gas. If so, wriggle the connector around. Try holding it onto the Switch. A bad connection is often an intermittent trouble spot on these years.

 

Cool man. You think it's the switch and not the control head?

 

Absent a low gas trouble code, that's usually the culprit - I'd check it first.

 

Sweet man. What do you think was the cause of the car driving wierd when I had the wire jumped and the compressor on? It sounded weird man...

 

Don't have a clue, but if there's no gas and the compressor is running, there's no oil to keep it lubed as the gas is what carries the oil. Compressors usually seize up and die shortly thereafter. By '93, GM built in a little more safety to keep that from happening, but if it you bypass it - kaboom!

 

when you add gas it has the oil in it right? Can I add oil on its own?