after my stud and head gasket install my a/c compressor will not turn on. no power to it. switched relay out, checked fuses in the cab. there is power to the relay and alll wires look good, run wire straight to battery and it will run so the compressor is still good. am i missing a fuse i dont know about??

 

Low pressure cutoff switch on top of the filter/canister should have wires plugged into it. Might have left that unplugged.

 

thanks i will look at that in a bit, also my tach only works sometimes, is it related maybe?