Vacuum Actuator
The vacuum actuators are vacuum servos used to operate valves inside the heater and A/C module. Valve position determines whether air comes out the floor outlets, panel outlets or windshield outlets and whether fresh (outside) air is drawn into the System or inside air is recirculated. Three actuators are used: two single-diaphragm actuators and one double-diaphragm actuator. The vacuum actuators are mounted on the heater and A/C module and are connected to the HVAC programmer by vacuum hoses.