Air Delivery/Temperature Control Circuit
The vacuum actuators move the air valves in the HVAC system (except the
temperature valve). Vacuum is applied to the actuators through the mode selector in the heater A/C control assembly. The mode selector consists of a rotary vacuum switch. The rotary vacuum switch supplies vacuum to the vacuum actuators according to the operating mode selected by the driver. A small servo motor moves the
air temperature actuator. The small servo motor positions the door according to the voltage level from the temperature selector in the heater A/C control assembly. The temperature selector is a potentiometer positioned by the temperature control knob on the front of the heater A/C control assembly.