Electra V6-231 3.8L VIN C SFI (1988)
Air Door Actuator / Motor: Description and Operation
Automatic Climate Controls
GENERAL DESCRIPTION
The air valves that control the heating and air conditioning air flow are operated by Vacuum Actuators. The valves that apply or vent vacuum to these
Actuators are solenoid operated. The valves are located in the Electronic Climate Control (ECC) Programmer and are powered by a solid state unit in
the Programmer. Push-button switches in the Heater and A/C Control Assembly signal the Programmer to operate the air valves.
Two temperature-variable resistors are connected to the control assembly to provide temperature information. The In-Car Sensor indicates the inside
air temperature. Circuits within the Heater and A/C Control Assembly use this information to determine whether the air should be heated or cooled to
bring the inside of the car to the selected temperature. The Ambient Sensor indicates the outside air temperature. The voltage signal from this sensor is
used to determine how much the air should be heated or cooled to bring the temperature in the car to the selected value as quickly as possible.
The functions of the Vacuum Valves and air valves are described below.
COMPONENTS DESCRIPTION
Air Mix Valve
The Air Mixture Valve is controlled by the Mode Valve Vacuum Actuator. With the valve in the COOL position, air is blocked from passing
through the Heater Core. This valve can be placed by the actuator in any position between COOL and WARM.
Air Inlet Valve
The Air Inlet Valve is open, permitting outside air to enter, in all the push-button selector positions except AUTO mode and 65°F temperature
setting. The In-Car Inlet is then opened, recirculating the inside air to get maximum cooling. When the Inlet Vacuum Valve is energized, vacuum
is applied to the Outside Air Valve Vacuum Actuator through the Vacuum Delay Porous Plug. This plug has a high resistance to air flow so that
the actuator and valve move slowly.
Mode Valve
The Mode Valve is moved by the Mode Valve Vacuum Actuator. This actuator has two vacuum chambers and can select three positions. In the
BI-LEVEL push-button position, neither valve is energized, and the Mode Valve is in its middle position, sending air to both the A/C Outlets and
the Heater Outlets. If the up valve is operated, the vacuum actuator moves the valve to position C. This is the position of the valve after the heater
push-button has been pressed. In A/C operation (except BI-LEVEL) the down valve is operated which moves the valve to position A.
A/C Defog Valve
The A/C Defog Valve is in position B for all the cooling functions. In these modes the A/C Defog Valve Vacuum Valve is energized, and vacuum
is applied to its vacuum actuator. When the Def push-button is depressed, the valve is de-energized. It vents the vacuum to the atmosphere and the
valve moves to position A. This directs the air flow to the Defog Outlets and the windshield. Refer to Diagrams / Vacuum and Vapor Hose for
Diagram of air valve positions. See: Diagrams
Note: For Diagnosis, please see Electronic Climate Control