Heat-Defrost Valve

The Heat-Defrost Valve is controlled by the Heat-Defrost Valve Vacuum Actuator. With the Mode Selector in any position but DEF (position 7), vacuum is applied to the actuator. The bellows contract and the Heat-Defrost Valve is pulled to position B. All air flows out the Floor and Side Window Air Outlets with some air bleed to the Windshield and Instrument Panel Air outlets.

No vacuum is applied to the Heat-Defrost Valve Vacuum Actuator with the Mode Selector in DEF. The bellows extend and the Heat-Defrost Valve moves to position A. Air flows out of the Windshield Air Outlets with some air bleed to the Floor, Instrument Panel and Side Window Air Outlets.