It took me a while, I had to watch the end of the race ending between the Bush brothers, hate em both, but at least a Chevy won! Then I had to refill my To-Kill-Ya drink and walk all the way out to my shop (30') to take a couple pics.
I figured it would be easier to show you how rather than firing up the CAD to generate a schematic...
I have the same HVAC controller you do (thought so)
You must be registered for see images attach
1st - you need to get this HP switch kit, you can get it anywhere, just make sure it's blue and comes with the 2-wire harness, green O-ring, and snap ring.
https://www.oreillyauto.com/detail/...4517359/1988/chevrolet/c1500-pickup-rwd?pos=1
2nd - Install it in the back of the compressor where the plug is (snap ring pliers)
You must be registered for see images attach
3rd - Cut the OE connector off the wire going to the original 1-wire switch connector and ground it to the T-Stat housing with all your other grounds.
You must be registered for see images attach
4th - Wire the new 2-wire HP Switch connector (I had red wire laying around) to the Low Pressure switch at your Drier/Receiver in series. Cut one of the wires, in this case I cut the light green one (makes no difference which), in 2 and splice the HP wires to those leads (I screwed in the pipe that goes from the Drier to the Evaporator to show the LP switch), make sense?
You must be registered for see images attach