Air Distribution System

Air enters the heater and ventilation system where the air is heated as necessary before being sent to the proper ducts and outlets for discharge into the passenger compartment. Within the heater case, doors guide the airflow in response to the positions of the temperature lever and the mode lever in the heater control unit.

Heater Core Description

The heater core is the main component of the heater system. The heater core is located inside of the heater and evaporator module. Engine coolant is pumped into the heater core from the engine whenever the engine is operating. The heater core fins transfers the heat from the engine coolant to the air passing over the heater core. The heater core has specific inlet and outlet tubes. The placement of the heater hoses should be noted prior to servicing the heater core or the heater hoses.

The temperature control is linked to the temperature valve by a flexible control cable. When you rotate temperature control counterclockwise to the full COLD position, the temperature valve is held snugly against the air entrance to the heater core. The following actions occur:

^ All of the airflow from the evaporator bypasses the heater core.
^ No heat transfer occurs.

When you turn the temperature control away from the full COLD position, the temperature valve begins to direct air to the heater core. This action allows air to flow through the heater core. The farther the temperature control is rotated clockwise, the more the temperature valve directs air through the heater core. The air discharge is warmer when most of the airflow is heated in this manner. The air discharge is warmer because the heated and unheated air flows join and mix together thoroughly beyond the heater core.

When you rotate the temperature lever clockwise to the full HOT position, the temperature valve blocks oft the passage that allows air to bypass the heater core. This action causes all of the airflow to pass through the heater core.

Ventilation Description

Ducts and Outlets

The mode lever operates the air flow control doors. The air flow control doors route the air (either heated or unheated, fresh or recirculated) through the following ducts and outlets:

^ The right IP duct
^ The center IP duct
^ The left IP duct
^ The right window defroster duct
^ The left window defroster duct
^ The windshield defroster nozzle duct
^ The center floor duct
^ The right IP louver
^ The center P louver
^ The left IP louver
^ The right window outlet
^ The left window outlet
^ The right windshield defroster nozzle outlet
^ The left windshield defroster nozzle outlet

Body Ventilation

The body ventilation system provides the passenger compartment with fresh, outside air. The body ventilation system routes this air through the same vents as the heated air.

The primary fresh air intake is located within the cowl panel. Air is drawn into the interior of the vehicle from the intake grille and is drawn out from the ventilator outlets in the body quarter panels.