Auxiliary Heating System

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).