Auxiliary Heater-A/C Control

With the ignition switch in the RUN position. 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 auxiliary heater-A/C control provides a ground path from G401 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.

The auxiliary temperature valve actuator receives voltage at all times through circuit 641 from the RR HVAC Fuse in the fuse block. It also receives ground from G401 through circuit 850. The auxiliary heater-A/C control sends a signal through circuit 955 to the auxiliary temperature valve actuator that is determined by the position of the temperature control. This signal is used by the auxiliary temperature valve actuator to determine the position of the temperature door.