Auxiliary Heater-A/C Control

When the ignition switch is in the RUN position, voltage is applied through the RR HVAC fuse 25 A (circuit 641) in the fuse block to the auxiliary heater A/C control. The temperature control potentiometer varies the voltage in circuit 641 from battery voltage to approximately 1.5 volts.

The auxiliary heater-A/C control provides a ground path from G401 through circuit 850. Vacuum regulates the control of air through the system. Various positions on the control cause the mode valves to mix and direct cooled, heated and outside air through the air ducts.

The auxiliary temperature valve actuator receives voltage through circuit 641 from the RR HVAC fuse 25 A in the fuse block. The actuator 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. The position of the temperature control determines the position of the actuator. The auxiliary temperature valve actuator uses the signal in order to determine the position of the temperature door.