The electrons can't tell the color of the plastic on the wires.
You don't need the high pressure switch.
You do need the 3 wire pressure transducer(sensor), connected to the high pressure side, wired to the 3800's PCM.
If the donor harness doesn't have a counter EMF diode on the compressor clutch, I add one. When the compressor clutch relay turns off the windings in the clutch itself will cause a counter EMF (voltage). That counter EMF voltage can damage the relay contacts over time. A counter EMF diode drains that voltage to ground.http://www.radioshack.com/p...e&filterValue=Diodes
Install the diode so the side with the line on it connects to the green wire. The side without the line on it connects to a black wire that then connects to ground.
[This message has been edited by phonedawgz (edited 09-08-2013).]