Front

Heater And Defroster:

DESCRIPTION
The heater provides heating, power upper and lower ventilation, ram lower ventilation, and windshield and side window defrosting.

OPERATION
The defrost mode operates with the right and left side window defroster ducts routing air to outlets on either side of the instrument panel. The duct work provides power center and outboard ventilation. Vents provide ram air ventilation.

Levers and a fan switch on the control assembly control system operation. These snap-in cables are attached to the modular duct, heater and control levers.

The fan switch controls the fan speed ("OFF" to "HIGH") in all modes. The vent mode features power vent ventilation.

Outside air enters the plenum and is driven by the fan to the temperature door. In the cold position of the temperature door; air by-passes the heater core to the vent opening and enters the passenger compartment through the vent duct and outlets in the center and at either side of the instrument panel.

The mode selector can blend air between modes. Placing the selector between "HTR" (heater) and "VENT" varies the proportion of air coming out of the heater outlets and vent outlets. With the mode selector in some midway position, air coming out of the vent outlets will be ambient temperature, while air out of the heater outlets will be mixed warm air, its temperature depending on temperature lever position.

In the "HTR" (heater) and defrost mode, outside air is driven by the blower to the temperature door which, depending upon its position as controlled by the operator, distributes all or some portion of the inlet air through the heater core. The vent door will prevent air entry into the vent duct and direct this ambient air to the mix portion of the heater module. The air is thus heated, mixed, and then directed into either the defroster duct or the heater outlet by the position of the mode valve and control lever. A small amount of air is bled to the side window defogger system.

The mode selector may also be positioned midway between "HTR" (heater) and "DEFROST" This will distribute the air to both the heater and defroster outlets proportional to lever position.