Heater and Defroster Valves

The heater and defroster valves are operated by a three-position defroster valve vacuum actuator attached to the defroster valve, which is in-turn connected by a link to the heater valve. When the defroster valve vacuum actuator is in the at rest (no vacuum) position, a blend of air is directed to the defroster and the floor outlets; as in DEFOG mode. When vacuum is applied to the lower side of the defroster valve vacuum actuator, the defroster valve is opened (full-down) and the heater valve is closed (full-down), allowing air to be directed to the defroster outlets; as in DEFROST mode. When vacuum is applied to the upper side of the vacuum actuator, the defroster valve is closed (full-up), blocking off the defroster outlets, and the heater valve is opened (full-up), allowing air to enter the floor outlets depending on the corresponding position of the mode valve; as in BI-LEVEL or LOWER modes.

There are adjustable outlets in the instrument panel and the driver's door. In addition there are two side window defogger outlets, one in each windshield side garnish molding. The instrument panel and door outlets are fed by the air distribution duct. The side window defogger outlets are fed by side window defogger ducts connected to the windshield defroster duct.