Defroster Valve And Heater Outlet Valve

The defroster valve and the heater outlet valve are connected together by a mechanical linkage allowing two valves to move together. The defroster valve and the heater outlet valve can be moved to one of three positions. The heater/defroster mode valve vacuum actuator consists of two chambers operated by two vacuum actuators.
When the A/C system is operated in the DEFOG. mode, both vacuum chambers are vented and both doors are in position B. Airflow is then directed to both the defroster outlets and heater outlets. When selecting the LOWER mode, the heater-A/C control energizes the heater solenoid, causing the heater/defroster mode valve vacuum actuator to move the defroster valve and the heater outlet valve to position A. In position A, airflow is sent to the heater outlets.
When selecting the FRONT DEFROST mode, the heater-A/C control energizes the defrost solenoid, causing the heater/defroster mode valve vacuum actuator to move the defroster valve and the heater outlet valve to position C. In position C, airflow is directed to the defrost outlets.