2008 Gmc Envoy Slt 4.2 A/C Compressor Ternimal Connection

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#1
Make
GMC
Model
Envoy
Year
2008
Miles
142,000
Engine
4.2
First time attempting a compressor on this truck and having trouble with the electric connections. The factory compressor that I took out has one terminal connection. The new compressor has a 2 terminal connections with one going to a sensor. I spoke with a representative from UAC and they told me to splice all the red wires together and all the black together, but I just dont think that is correct. I have attached pictures of old and new compressor with the wiring. If anyone knows or have ran into this before your help would be MUCH APPRECIATED!!
 

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#2
Without a whole lot of fact checking, here's my opinion....your old system didn't have that sensor, so ignore it and just connect your original wires to the clutch wires.
 

billr

wrench
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#3
I concur. Ignore the 4-pin BLK connector and connect your harness to the GRY 2-pin one on the new compressor.
 
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#5
GM at one time always used a two terminal connector, clutch coil has two ends one that goes to ground other that goes to the clutch relay contacts that when closed provides 12 V to the other end. An electromagnet that pulls in the clutch to engage the compressor.

Japanese came out with the one terminal connector in the 80's that went directly to the clutch coil, the other one was grounded to the compressor and if you got road corrosion in the mechanical parts, would not get a good ground. Compressor coils generally pull about 4 amperes.

More than likely your compressor has a hydraulic operated variable displacement, the newest ones are electric, so you have three wires. Clutch coil should have about 3 ohms of resistance, if you are applying 12V to zero ohms, something will burn up.