The little two prong connector with the diode jumper is for the compressor. Your '88 is probably a little more sophisticated then our older models, but basically the same. My Pontiac has a major ground wire in the harness that rests on the intake manifold and is bolted to the compressor bracket. Nothing would work without that ground. This might help figure it all out-http://www.maliburacing.com/wiring_diagrams/FourSeasonAirConditioner.jpg
Alright so while I'm waiting on a blower motor resistor, orfice tube and drier I was checking the wiring today. Correct me if I'm wrong, but shouldn't the pressure switch connector have constant power when the AC is on? Also the red wire that is cut has no power when plugged into the body harness. Only the green wire on the body harness side (the AC harness plugs into this) has power when the AC is on.That would make sense that the red wire is cut if it went down to the starter on the 307. Now I do have some wiring still on the car. The plug that has the red wire cut I believe plugs into a body harness which is still on the car.
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