Controls

The control assembly in the instrument panel contains a blower switch, a mode lever, and a temperature lever. The controls are lit when the headlamps are on. Electrical power is provided by the instrument panel lighting circuit from the instrument panel harness.

Brightness of the dial illumination is controlled by the instrument panel dimmer switch. The control assembly bulbs are in parallel with the radio bulb, the ashtray bulb, and instrument cluster illumination bulbs.

TEMPERATURE LEVER
The temperature lever operates the temperature control cable that goes to the heater module. When the temperature lever is in the "COLD" or the lower end of the slot, all of the air delivered by the heater system is unheated. When the temperature lever is in the "HOT" or the upper end of the slot, all of the air passing through the heater module is heated before it is discharged. Intermediate positions of the temperature lever result in a mixture of heated and unheated air to provide more moderate air temperatures.

MODE LEVER
The mode lever operates two control cables that go to the heater module. The two cables are the defrost control cable and the vent control cable. Each cable operates a crank lever and shaft that controls the position of an air valve in the heater module. Mode lever positions are "HEATER," "VENT" and "DEFROST" ("DEFROST" position is indicated by the defrost symbol).

BLOWER SPEED CONTROL
The blower switch is a four-position switch that provides three blower speeds plus an "OFF" position. The blower switch receives power from a 20 ampere fuse in the fuse block when the ignition is "ON." In the two intermediate speed positions, the circuit continues through the heater wiring harness to a resistor near the blower motor.

For "HIGH" blower speed, the circuit bypasses the resistor. From the resistor assembly, the circuit goes to the blower motor terminal. The blower motor circuit is complete from the blower motor through another wire in the heater wiring harness that is grounded to the dash panel sheet metal below the instrument panel.