Front Blower Motor

The front blower motor controls operate by supplying voltage to the motor through the switch and the relay contacts. Battery voltage is available from HTR-A/C fuse 12 through CKT 141 (BRN) to the heater and A/C controller when the ignition switch is in the RUN position. This voltage is available through CKT 119 (WHT) to the blower switch of the heater and A/C controller, when the mode switch of the heater and A/C controller is in one of the following positions:
^ Defrost
^ Blend
^ Heat
^ Vent
^ Bi-level
^ A/C
^ MAX A/C

Voltage through CKT 119 (WHT) provides for the operation of the blower motor at the following speeds:
^ LO
^ Medium 1
^ Medium 2

Voltage through CKT 119 (WHT) also provides for the operation of the blower motor relay in the blower motor resistor/relay. The BLOWER fuse supplies battery voltage for the blower motor HI speed at all times through CKT 542 (RED) to the blower motor resistor/ relay. The blower motor and the blower motor resistor/ relay ground at ground G103 through CKT 150 (BLK). Placing the blower motor switch in the LO position applies voltage from the switch contacts through CKT 60 (YEL) to the blower motor resistor/relay. The blower motor remains de-energized. Voltage is available through the three resistors to the blower motor. Grounding the blower motor through the blower motor resistor/relay establishes a current flow. As a result, the blower motor operates. The voltage drop through the three resistors limits the motor operation to the lowest speed.

Placing the blower motor switch in the medium 1 position applies voltage to the blower motor resistor/relay through CKT 63 (TAN). The current must flow through only two resistors in order to reach the motor. With the increased voltage at the motor, the motor operates at a faster speed.

Placing the blower motor switch in the medium 2 position applies voltage to the blower motor resistor relay through CKT 72 (LT BLU). The current must flow through only one resistor in order to reach the motor. With the increased voltage at the motor, the motor operates at a still faster speed. The blower motor resistor has automatic reset thermal fuses for each resistor. These fuses automatically open with a high current flow. When the current stops, the fuse cools down. The fuse then resets automatically.

Placing the blower motor switch in the HI position applies voltage through CKT 52 (ORN) to the blower motor relay coil in the blower motor resistor/relay. Because the coil grounds at ground G103 through CKT 150 (BLK), the relay coil energizes. Energizing the relay coil closes the relay contacts. Energizing the relay coil also applies voltage from BLOWER fuse to the blower motor. Because of no voltage drop through any of the resistors, the blower motor operates at the highest speed.