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 when the ignition switch is in the RUN position to the heater and A/C controller through CKT 141 (BRN). This voltage is available to the blower switch of the heater and A/C controller, when the mode switch of the heater and A/C controller is not in the OFF position. This power is for operation of the front blower motor at the low and medium speeds only. This power also operates the blower motor relay in the blower motor resistor/relay. The relay energizes in order to operate the blower motor in the HI speed. Battery voltage is available at all times from the HVAC MaxiFuse® to the blower motor resistor/relay through CKT 542 (RED). The voltage is available for the operation of the front blower motor at high speed.

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. The current flows through the three resistors and the normally-closed relay contracts to the blower motor. CKT 65 (PPL) pigtail wire provides operating voltage to the blower motor from the blower motor resistor/relay. Grounding the blower motor resistor/relay at ground G103 through CKT 150 (BLK) establishes a current flow. The voltage drop through the three resistors limits the motor operation to the lowest speed.

The blower motor switch in the medium 1 position applies voltage to the blower motor resistor 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.

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. The current flow heats the fuse element. When the current stops, the fuse cools. The fuse then resets automatically.

The blower motor switch in the HI position applies voltage through CKT 52 (ORN) to the blower motor relay coil. Because the coil grounds at ground G103 through CKT 150 (BLK), the relay coil energizes. Energizing the relay coil closes the relay's normally-open contacts. Energizing the relay coil also applies voltage from HVAC fuse to the blower motor. Because the operating current bypasses the resistors, the blower motor operates at the highest speed.

The rear auxiliary blower motor controls operate by grounding the auxiliary blower motor relays through the switch contacts. Battery voltage from RR BLOWER fuse is available at all times to the normally-open contacts of each of the three auxiliary blower motor relays. When one of the relays operates, voltage is available either directly or indirectly to the auxiliary blower motor. Because the auxiliary blower motor grounds at ground G400 through CKT 150 (BLK), the motor operates.

Battery voltage is available from RR HVAC fuse 24 through CKT 341 (BRN) to the coils of the three auxiliary blower motor relays. This voltage is available when the ignition switch is the RUN position. This voltage operates the relays. The auxiliary blower motor switch grounds the coil of the selected relay through CKT 15 (BLK) through ground G400. When the relay coil grounds through the auxiliary blower motor switch, the current flows through the relay coil in order to close the relay's normally-open contacts. Voltage is available to the relay contacts at all times through CKT 1542 (RED) from the HVAC MaxiFuse®. When the relay contacts close, this voltage operates the motor.

Placing the auxiliary blower motor switch in the LOW position grounds the coil of the auxiliary blower motor low speed relay through the wire for CKT 1926 (DK BLU) and CKT 60 (YEL). The relay's contacts close and apply operating voltage in CKT 1176 (YEL). The current flows through both the resistors in the auxiliary blower motor resistor and through CKT 1172 (YEL) to the auxiliary blower motor. The voltage drop through the two resistors limits the auxiliary blower motor to the lowest speed.

Placing the auxiliary blower motor switch in the medium position grounds the coil of the auxiliary blower motor medium speed relay through wire for CKT 1925 (RED) and CKT 63 (TAN). The relay's contacts close and apply operating voltage in CKT 1072 (LT BLU). The current flows through only one resistor in the auxiliary blower motor resistor and through CKT 1172 (YEL) to the auxiliary blower motor. The voltage drop through the single resistor allows the operation of the auxiliary blower motor at a higher speed.

Placing the auxiliary blower motor switch in the HIGH position grounds the coil of the auxiliary blower motor high speed relay through wire for CKT 1924 (WHT) and CKT 52 (ORN). The relay's contacts close and apply operating voltage directly in CKT 1172 (YEL) . The current flow bypasses the resistors in the auxiliary blower motor resistor. The full battery voltage allows a high speed of operation for the auxiliary blower motor.