[BNaylor]

I am assuming by bypassing the A/C Clutch relay you jumped pins 87 to 30 at the relay contacts to get the clutch to activate?

The clutch diode is after the relay at pin 87 and connected in parallel to the Compressor Clutch Coil so if you jumped contacts 30 and 87 then you can rule it out.

The PCM supplies solely a ground/low signal so you can apply a ground to pin 86 which is one side of the relay coil just to double check the relay is energizing. Pin 85 on the other side of the relay coil has the 12 volts.

According to the GM wiring diagram the PCM needs A/C Clutch Request input from the climate control unit so check that too. Also, the PCM may not send the ground/low if the refrigerant charge is either too high or low. You can ohm out the signal line from the PCM at C2 pin 39 to the clutch relay pin 86 to make sure the wiring is good or there is continuity.