Auxiliary Heater-A/C Control

With the Ignition Switch in RUN, voltage is applied through the RR HVAC fuse (circuit 641) in the fuse block, to the Auxiliary Heater-A/C Control. The voltage from circuit 641 is varied from Battery voltage to approximately 1.5 volts by the Temperature Control Potentiometer. The Control Assembly provides a ground path through circuit 850. Control of air through the system is regulated by vacuum. At various positions on the control, mode valves mix and direct cooled, heated, and outside air through the air ducts.