hello folks,have a problem with no power getting to the ac compressor,ive got correct gas pressure and bypassed the pressure swich,the on switch works ive got power going out and then cant see where it goes.cant find the clutch relay either so i can check that.Any ideas or a diagram would be helpfull,much appreciated
M series machines have an electronic de-icing controller, ive replaced more than one of them. if you raise the cab, on the RH side of the HVAC box you should see something that looks like a thumb drive that the harness plugs into. disconnect and jump the wires on the harness side and see if the compressor kicks on. there is a 5 second or so delay built into the system before the compressor will kick on. all "control" for the HVAC system comes from one of the controllers. i did run across one that the controller output was "dead" and would not let the AC kick on.