Mode Valve

The mode valve in the at-rest (no vacuum) position, allows a blend of air to the instrument panel and the floor outlets; as in BI-LEVEL mode. The mode valve can be opened (full-down) or closed (full-up) by applying vacuum to one side or the other of the three-position mode valve vacuum actuator. When opened (full-down) by applying vacuum to the lower side of the vacuum actuator, air will exit the instrument panel outlets (air is blocked off from entering the floor outlets); as in UPPER mode. When closed (full-up) by applying vacuum to the upper side of the vacuum actuator, the instrument panel outlets will be closed off and air will be delivered to the floor outlets depending on the corresponding position of the heater valve; as in LOWER or DEFOG modes.