I'm guessing you and I are having similar problems.
My AC cut out about four years ago -- yeah, a long time -- but I finally got around to fixing it.
I loaded up the refrigerant, checked the pressure, no leaks. When I went to test out the AC, the compressor clutch doesn't engage. Here's what I've tried:
I've tested the voltage across the connector, and I get zero.
I've checked the fuses for the AC, they test fine.
I've jumped the clutch directly from the battery, and that powers the compressor fine.
I've tested the in-line diode between the connector and the relay, and the diode functions fine.
I've swapped power relays to test the relay, and the car starts fine.
So, I'm at a loss here... what should I try looking for now?