Control Assembly, HVAC

RECIRCULATION/FRESH AIR CONTROL

The recirculation feature is driven by the air inlet valve. The valve is linked to a vacuum actuator that is controlled by the mode knob of the control assembly. The valve allows fresh (outside) air to enter the passenger compartment when open. The valve will force the passenger compartment air to be recirculated when the valve is closed.

TEMPERATURE CONTROL

Temperature is controlled by the position of the temperature knob on the control assembly. A cable connects this knob to the temperature valve. It controls air flow through the heater core, as the temperature knob is moved through its full travel. The position of the temperature valve is independent of mode selection. The temperature cable attaches to the right side of the HVAC module.

MODE CONTROL

The mode of operation of the control assembly is determined by the position of the mode knob. The mode knob controls a vacuum switch that supplies engine vacuum to the appropriate vacuum actuator(s) for the mode selected. Vacuum lines are molded to a connector that is attached to the vacuum switch.

BLOWER SPEED CONTROL

The blower speed is controlled by a knob which actuates a switch. The blower circuit is open in the "OFF" mode. In all other modes the blower has 4 speeds to control the amount of air that flows through the HVAC module.