03 expedition

my a/c just stopped working a couple of days ago. no warning, no noises, and it was ice cold before it stopped working. i unplugged the low pressure switch and jumped the two prongs and the clutch didnt engage. is there a fuse or a relay that provides power to the a/c compressors clutch?? it is activated by ground the clutch assembly right? so there should be a constant 12 volts to the compressor til it is grounded i think. any ideas??

The clutch on the compressor is grounded all the time. The control for it is the switch on the dash which goes to the low pressure switch and then the relay for the AC.