The rear heater and air conditioning (A/C) functions are controlled by the rear heater switch and the rear A/C switch respectively. The battery voltage is provided to the rear heater-A/C relay (rear) coil by the HTR-A/C fuse 12 and CKT 141 (BRN). The coil is grounded by CKT 850 (BLK) cavity B9 of the rear heater-A/C relay (rear). The rear heater-A/C relay (rear) is energized when the ignition switch is in the RUN position. The rear-A/C relay (rear) provides the battery voltage to the rear heater switch and the rear A/C switch. The RR HEAT/ A/C fuse provides battery voltage to CKT 1040 (ORN) cavity A9. Cavity A9 is the common contact of the rear heater-A/C relay (rear). The common contact and the normally open contact are connected when the rear heater-A/C relay (rear) is energized. The connection provides voltage to CKT 1923 (ORN) cavity B7 of the rear heater-A/C relay (rear). The rear heater-A/C relay (rear) supplies the voltage to the rear heater and the rear A/C switches.

The blower speeds are controlled by the rear heater switch for the rear heater blower motor. The blower speeds are controlled by the rear A/C switch for the rear A/C blower motor. CKT 1923 (ORN) provides the battery voltage to the rotary contact of both of the switches. The full current flow is provided to the following circuits when either switch is in the HIGH position:

The motor is grounded through CKT 1150 (BLK) and CKT 1250 (BLK) respectively. The motor will operate at full speed when the motor is grounded.

Limiting the current flow through the rear heater blower motor and the rear A/C blower motor results in slower blower speeds. Place resistance in the current path for the rear blower motor in order to limit the current flow. A current path is provided through the following route:

1. CKT 1925 (RED) cavity A of the rear heater resistor pack for heater
2. CKT 1072 (LT BLU) cavity A for the A/C
3. Through the rear A/C resistor pack connecting through the respective motor.

The blower switch is placed in the LOW position in order to attain a lower speed. Lowering the speed provides a current path through the following items:

The circuit is then completed through the resistor connector to cavity C and the resistor connected to cavity B.

This places 2 resistors in the current path. The current to the motor is reduced more when the 2 resistors are in the current path.

When the heater A/C control valve solenoid is energized heated engine coolant is provided to the rear heater core. The solenoid is powered by a second set of contacts in the rear heater switch. Battery voltage from CKT 1923 is provided through the following switch positions:

These positions provide battery voltage from CKT 1596 (GRY/BLK) through the convenience center to the heater A/C control valve solenoid. The solenoid is grounded at CKT 850 (BLK). The solenoid will be energized when the solenoid is grounded.