Heater System

The heater system provides heating, ram air and power ventilation and windshield defrosting. Outside air is drawn from the plenum at the base of the windshield into the heater module by the blower fan. Additional outside air, called ram air, is forced into the heater module by the forward movement of the vehicle. Within the heater module, the air is heated as required, then routes through ducts to the proper outlets for discharge into the passenger compartment. A control assembly in the instrument panel allows the operator to control blower speed, mode of operation, and temperature of the air coming from the heater system.
The heater module contains components that heat the air flowing through it and direct the air to the proper ducts and outlets. These components are enclosed inside a two-pan housing. The front housing mounts to the front of the cowl panel in the engine compartment. The rear housing mounts to the rear of the cowl panel in the passenger compartment under the instrument panel.

Auxiliary Heater (C36)

An optional auxiliary heater provides heating to the rear of the vehicle. This unit operates independent of the standard heater, and is regulated through its own control on the instrument panel. This system consists of a separate heater core and blower fan.

Heater hoses extend from the unit to a vacuum operated water valve where they connect to the standard heater hoses.

A three-position vacuum operated water valve, cuts off coolant flow in the off position, eliminates radiant heat, and reduces coolant flow in the "LO" and "MED" positions.

CONTROLS

Blower Speed Control

The three-speed blower switch "Lo," "Med" and "HI" is located in the instrument panel, above the radio. In addition to controlling blower motor speed, the switch also triggers an electro-mechanical valve to control coolant flow to the auxiliary heater core.

In the "Lo" speed position, the circuit continues through the heater wiring harness to two resistors in the blower motor resistor relay.

In the "Med" speed position, the circuit continues through the heater wiring harness to one resistor in the blower motor resistor relay.

In the "HIGH" speed position, the circuit continues through the heater wiring harness to the blower motor resistor relay, and closes the relay's normally open contact to provide full power to the blower motor from the HVAC maxifuse(R).