Decelerator (STD cab) Position potentiometer voltage is too high
Reverse clutch is not calibrated
Aux 3rd Raise Coil solenoid shorted to 12 volts.
Low pressure switch (-) input shorted to ground
Reverse clutch is not calibrated
If Inadequate air flow is problematic, so clogged air filters, evaporator core air flow restricted, faulty blower fan motors, defective blower switch or faulty wiring or loose connections.