Heating and Air Conditioning: Description and Operation

All models use a Blend-Air type heater. Outside air enters the heater through the cowl opening and passes through a plenum chamber to the heater core. Hood louver air intake or air intake at rear of hood at windshield wiper opening must be kept free of snow, ice, and other obstructions for heater or air conditioning to pick up sufficient outside air. A temperature control door in the heater housing directs incoming air through the heater core and/or the heater core by-pass. The amount of blend (heated and non-heated air) is determined by the setting of the temperature lever on the instrument panel. Direction of the blended air is controlled by the Heat-Defrost lever on the instrument panel.

The blower switch, in conjunction with a resistor block, controls the speed of the blower motor, and hence the velocity of the air flow from the heater outlets.

The resistor block consists of two helically wound wire resistors connected to terminals which are mechanically attached to a glass-filled phenolic board. This assembly is bolted to the plenum.

The blower switch controls the blower motor speed by selectively connecting in series, one, two or none of the resistors to the blower motor.

A self-adjusting clip, on each of two control cables has been incorporated to simplify cable adjustment. This clip snaps onto the control cable core wire and will slide along the wire under a specific load to provide an automatic cable adjustment.