Heater-A/C Control

With the Ignition Switch in RUN, voltage is applied through the HVAC/DRL Fuse (circuit 241) in the fuse block. The RADIO Fuse (circuit 640) in the Underhood (UH) Electrical Center provides voltage to the Heater-A/C Control at all times. The voltage from circuit 241 is varied from Battery voltage to approximately 1.5 volts by the Temperature Control Potentiometer The Control Assembly provides a ground path through circuit 150. 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.