need help finding a/c compressor wires on 85 GMC - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72farmer · 02-03-2018, 03:17 PM

I have a 85 GMC Sierra Classic.I am going to try to get the a/c going.I can't seem to find the wire going to the compressor.The compressor has 2 wire terminals on it.I thought most older vehicles that had a/c on them only had 1 wire to compressor.The negitive ground was done through engine ground and mount.

I need to know what color wire or wires would come from pressure switch and go to the compressor.

natedogg · 02-03-2018, 08:11 PM

The wires are green. As you can see, the a/c compressor has its own Lil harness that branches off. Went out and snapped a pic of the Lil harness on my 85. I think I have a extra harness out in my garage, if you need?

*gmachinz* · 02-03-2018, 08:23 PM

The AC subharness on the right in the pic is the one you need. The dark green is compressor clutch +12V and the light green wire goes to carb idle stop solenoid. The AC comp clutch negative grounds to your thermostat housing bolt.

72farmer · 02-03-2018, 09:05 PM

Thanks for the help.I found it.

Wwes · 02-03-2018, 11:15 PM

Anyone know what year they had a high-pressure switch on the back of the compressor?

02-03-2018, 03:17 PM	#1
72farmer Registered User Join Date: May 2009 Location: Hazel Green AL Posts: 286	need help finding a/c compressor wires on 85 GMC I have a 85 GMC Sierra Classic.I am going to try to get the a/c going.I can't seem to find the wire going to the compressor.The compressor has 2 wire terminals on it.I thought most older vehicles that had a/c on them only had 1 wire to compressor.The negitive ground was done through engine ground and mount. I need to know what color wire or wires would come from pressure switch and go to the compressor. Last edited by 72farmer; 02-03-2018 at 03:34 PM.

02-03-2018, 08:11 PM	#2
natedogg Registered User Join Date: Dec 2013 Location: West, TN Posts: 312	Re: need help finding a/c compressor wires on 85 GMC The wires are green. As you can see, the a/c compressor has its own Lil harness that branches off. Went out and snapped a pic of the Lil harness on my 85. I think I have a extra harness out in my garage, if you need? Attached Images

02-03-2018, 08:23 PM	#3
gmachinz Account Suspended Join Date: Jun 2011 Location: Des Moines, IA. Posts: 4,143	Re: need help finding a/c compressor wires on 85 GMC The AC subharness on the right in the pic is the one you need. The dark green is compressor clutch +12V and the light green wire goes to carb idle stop solenoid. The AC comp clutch negative grounds to your thermostat housing bolt. Attached Images

02-03-2018, 09:05 PM	#4
72farmer Registered User Join Date: May 2009 Location: Hazel Green AL Posts: 286	Re: need help finding a/c compressor wires on 85 GMC Thanks for the help.I found it.

02-03-2018, 11:15 PM	#5
Wwes Registered User Join Date: Apr 2017 Location: FL Posts: 144	Re: need help finding a/c compressor wires on 85 GMC Anyone know what year they had a high-pressure switch on the back of the compressor?



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.