A/C wiring question

[splatrd]

I searched the reference section and downloaded the wiring manual, but am still having trouble sorting out wiring for compressor clutch. Previous owner installed LS1 and ripped out all old wiring for A/C. Did the factory system use a relay for compressor clutch? If so where was it located? I have not pulled dash apart yet to trace the wire from control panel. I am planning on installing R4 compressor from 88-91 Blazer and want to wire it up like it was originally.

Thanks

 

[1987 GMC Jimmy]

I searched the reference section and downloaded the wiring manual, but am still having trouble sorting out wiring for compressor clutch. Previous owner installed LS1 and ripped out all old wiring for A/C. Did the factory system use a relay for compressor clutch? If so where was it located? I have not pulled dash apart yet to trace the wire from control panel. I am planning on installing R4 compressor from 88-91 Blazer and want to wire it up like it was originally.

Thanks

There's no clutch relay that I've ever heard of. The voltage is mediated by the low pressure switch on the accumulator.

 

[splatrd]

Ok thanks, when looking thru the wiring manual there was one listed. However I could never find any evidence of one. I guess I will have to pull dash apart and chase wire that is supposed to go to the clutch.

 

[1987 GMC Jimmy]

It originates from the selector switch as a light green wire, which goes to one side of the switch. The other side was a dark green wire that goes to the compressor. In its original form, 12V would also go to the fast idle solenoid, which had a lever that pushed on the throttle arm to raise the idle a little bit. You'll need that if you're running a carb. I don't know anything about wiring in a Gen III motor so I don't know if you need a signal sent to the ECM if you're running EFI. The OBD1 ECM's did get a compressor signal, though.