Air Delivery System

AIR DELIVERY SYSTEM
The heating and air conditioning module incorporates most of the air delivery components into one assembly.

Air utilized by the Electronic Climate Control (ECC) system is drawn into the module through an opening at the base of the windshield and routed to the blower. The blower directs the air through the evaporator core where it is filtered, dehumidified and cooled to approximately 2°C (35°F). It is then heated as required by passing through and around the heater core. This air is then directed by air valves to the A/C outlets in the instrument panel, to the heater outlets at floor level, or to the defroster outlets depending upon the mode selected. Air exits from the interior by passing through the air exhaust grilles located in the rear quarter. This provides positive air flow even when windows are closed. The components comprising the air delivery system are described as follows:

Air Intake
Air Intake is controlled by an air inlet valve and a vacuum actuator that controls the position of the valve. The air inlet valve has two positions. With no vacuum applied to the actuator, the valve is in its down position, blocking off the recirculating air opening and allowing only outside air to enter the blower.

When vacuum is applied to the actuator, the valve is moved to its "up" position where it blocks most of the outside air and allows approximately 90 percent of the total air supply drawn in by the blower to be recirculated from the passenger compartment.


Blower Motor
The blower motor is located left of center in the A/C module. The blower motor is a brushless type and operates a various speed determined by the Air Conditioning Programmer. The balance of the brushless blower motor is very sensitive to handling. When the blower motor is serviced, care should be taken to minimize the amount of handling of the blower motor.

















AIR DISTRIBUTION
The air is directed into the air distributor assembly. An up/down valve sends air to the heater outlet assembly, up through the air distributor to the A/C or windshield outlets, or to both the heater outlet and the A/C outlets, or defrost outlets.

The three position up/down valve is operated by a vacuum actuator. In its relaxed location, the valve is m the middle position allowing air to flow upward through the A/C outlets or windshield defroster, and downward through the heater outlet. With vacuum applied the valve is pulled downward. This allows air to flow upward through the air distributor to either the A/C outlets or the defroster outlets, but cuts off the flow to the heater outlets. With vacuum applied the valve is pulled upward allowing air to flow downward toward the heater outlets. In all three positions a small amount of air is directed to the side window defroster outlets and rear seat outlets.

Air flow upward through the air distributor is directed to either the A/C outlets or the windshield defroster, depending upon the position of the A/C defroster valve. In its relaxed position the valve is rearward, blocking the air flow to the A/C outlets and directing air to the windshield. The valve will move forward when vacuum is applied to its actuator, directing the air to the A/C outlets.


Air Conditioning Outlets
Four main outlets are located in the instrument panel, one on the left side, two in the center and one on the right side. A small amount of air is directed to the side window defroster outlets and the heater outlet to cool the floor. The main outlet provides an airstream direction that can be controlled independently. The outlet may be rotated and the knob in the center of each outlet may be adjusted to provide the desired air direction. Air flow may be stopped altogether from each outlet by moving the shut-off lever next to the outlets to the fully closed position.

Defroster Duct
A unitized defroster outlet delivers defrosting air to both sides of the windshield. It is attached to the top of the A/C module and is located on top of the instrument panel.

Heater Outlet
The heater outlet is located along the bottom of the A/C module and near the center of the underside of the instrument panel. It distributes air to the left and right sides of the front floor and also directs air to the rear seating area.

Rear Seat Outlet
Two rear seat outlets are located on the back of front seat armrest. Each outlet provides an air stream which can be directionally controlled independent of the other.