Air Distribution System

Air Flow Diagram:

Air Distribution System:

Vacuum Harness Routing:

Cross Car And Rear Seat Ducts:

Air utilized by the HVAC system is drawn into the blower module through the air inlet assembly at the base of the windshield and routed through the blower. The blower forces the air through either the evaporator core where it is dehumidified and cooled, or through the heater core, where it is warmed. Now conditioned, the air is directed by air valves in the A/C module to the outlets in the instrument panel, to the heater outlets at the floor, front and rear, or to the defroster outlets, depending upon the mode selected by the driver.

Air Inlet Assembly

The air inlet assembly provides outside (fresh) or inside (recirculated) air to the blower depending on the mode selected. The inlet air is varied by an actuator that is controlled by the A/C programmer.

Blower Motor

The blower consists of a permanent magnet type motor and "squirrel cage" type fan. The blower operates at various speeds determined by the HVAC programmer.

The blower motor is cooled by having a small portion of blower output air recirculated through the motor housing by a rubber tube.

The blower is located at the right side of the HVAC blower module near the right of the vehicle.

HVAC Blower Module

The HVAC blower module houses the blower motor and fan assembly, evaporator core, and blower control module or blower Resistors. The module is located under the hood just beneath the relay center.

The blower collects air from the Air Inlet Assembly and forces it through the blower module and evaporator core.

Vacuum Lines

Vacuum lines are molded to a connector that is attached to the programmer assembly. The lines are easily repaired to eliminate the need for harness replacement in case of leakage or hose collapse.

Vacuum Reserve Tank

The purpose of the vacuum reserve tank is to store vacuum for use by the HVAC system through all ranges of vehicle operation. The vacuum reserve tank is located under the right front fender.

During heavy acceleration, the vacuum supply from the intake manifold drops. A check valve in the vacuum harness leading to the vacuum tank maintains vacuum so that, under load conditions, vacuum will be available for continuous use by the HVAC control system.

Ducts and Outlets

The ducting is the network of tubing used to get conditioned air from the A/C module to the instrument panel and rear seat outlets. There are two major ducts that are attached to the air distribution chamber.

1. Cross Car Ducts.
2. Rear Seat Duct.

The cross car ducts are attached to the back of the instrument panel. It receives air from the distribution chamber and delivers it to the instrument panel outlets and pass through ducts to the side windows.

The rear seat duct receives air from the bottom of the distribution chamber and delivers it through two outlets at the rear of the front seat center arm rest or console.