Fan clutch issues

Hey everyone, working on a '02 Pete 379, fan clutch wont engage until key is off. Thought we had it solved with the clutch solenoid, but no. I checked my manual override switch, pretty sure it's good, I checked that it was getting power, it was, but it also had power on the wire going out! checked the high pressure switch harness and it has power on both wires as well, went to the low pressure switch and it only had power on the one side like it should until its plugged in then both wires are hot (as it should due to the a/c not running).
Wondering if it is the thermal switch, which I can't find?!! Any help is greatly appreciated!