Circuit Operation

The Blower Motor is a variable speed motor, which runs at a speed proportional to the applied voltage. The higher the voltage applied to the motor, the faster the speed.

While the Ignition Switch is in the "RUN" position, battery voltage is applied to the Heater-A/C Control through I/P Fuse #17. With the Heater-A/C Control in the "OFF" position, no voltage is supplied to the Blower Motor.

When any other mode position is selected, voltage is applied to the Heater-A/C Control Blower Switch, and Blower Motor Resistor if not in "HI."

With the Heater-A/C Control Blower Switch in the "LO" position, voltage is applied to CKT 60 from the Heater-A/C Control Blower Switch to terminal "A" of the Blower Resistor, through the resistor to the relay contacts in the high Blower Relay, and the Blower Motor. The Blower Motor runs at low speed.

As the Heater-A/C Control Blower Switch is moved through positions "M1" and "M2", the switch bypasses part of the Blower Resistor allowing more voltage to be applied to the Blower Motor, which will increase its speed.

When the Heater-A/C Control Blower Switch is in the "HI" position, voltage is applied through CKT 52 to the coil of the High Blower Relay. The High Blower Relay energizes, removing the Blower Resistor from the circuit. Battery voltage is then applied directly to the Blower Motor through the High Blower Relay contacts. The motor runs at maximum speed.