03 T600 Hvac wiring diagram (AC clutch wont engage but can jump it)

2003 Kenworth T600 Cummins ISX
I have a t600 there is no power to the clutch the high and low switches ohm out. The high switch buy the condenser has 12v the low pressure switch near the fire wall doesnt show any. This has a box by were the pipes go into the firewall that tells me the refrigerant is low from a flashing red light but we jumped the compressor and charged it. AC works find if you jump the compressor.

Does anyone have a wiring diagram ( could figure this out) t600 2003 with sleeper.
Does the fan kick on when you turn the AC on to cool the condenser?
Could the low/high switches be bad and still ohm out?