air con electrical issue

hi all. i have a 2003 disco, last fall my condesser fan went bad (small rock jammed the fan) frying all the wires in the same bundle.i replaced the wires, but now my air conditioning pump doesnt engage. ie no power to the clutch. there are no fault codes. i am suspecting that the power back fed to the atc and fried somthing.
what should i be looking for? and what are the sensors that limit the ATC unit from sending the output to turn on the compressor clutch?

thanks for your help everyone.