Air Delivery

ELECTRONIC A/C CONTROL HEAD

With the Ignition Switch in "RUN," voltage is applied through Fuse 4 to the Electronic and A/C Control Head. The operating mode of the system is determined by buttons on the front panel. Ground signals determine which air valves are to be operated as well as the position of the Temperature Valve.

SOLENOID MODULE

The Solenoid Module contains the solenoid valves that control the vacuum actuators. When the solenoids are de-energized, the valves vent the vacuum actuators, allowing the vacuum actuator to return to the vent position.

RECIRCULATION VALVE

The Recirculation Valve closes off the outside air inlet so that the air from the inside of the car is recirculated through the A/C System for maximum cooling. The outside air inlet is closed when vacuum is applied to the actuator. When the vacuum actuator is vented, the Recirculation Valves close off the in-car air inlet which allows outside air to be drawn into the car.

TEMPERATURE VALVE

The Temperature Valve determines how much air flows through the Heater Core, which determines the temperature of the air to the outlets. It is moved by an electric motor which is part of the Air Mix Door Actuator. The position of the valve is determined by the temperature selected at the Electronic A/C Control Head.

HEAT/DEF

The HEAT/DEF Valve determines whether air flow will be directed to the windshield defrost outlets. With no vacuum applied to the actuator, the valve is positioned to allow air flow to the windshield defrost outlets.

UPPER/LOWER MODE

The UPPER/LOWER MODE Valve can assume three positions and is operated by a bi-directional vacuum actuator which can move the valve to either of two positions. If no vacuum is applied to either vacuum actuator, the valve is in midposition. Air Flow with the valve in midposition will be delivered to the panel outlets and the floor outlets. When the BI-LEVEL Solenoid (#3) (red vacuum hose) is operated, the valve is positioned to direct air flow to the floor outlets. When the A/C Solenoid (#5) (tan vacuum hose) is operated, the valve is positioned to direct air flow to the panel outlets.

HEATER WATER VALVE

The Heater Water Valve determines whether water will flow through the Heater Core or not. When the Heater Water Valve Vacuum Actuator is operated, the Heater Water Valve will close, stopping water flow into the Heater Core.