Controls

Module And Controls:

Module Airflow:

Mode Airflow Distribution:

Three knobs in the instrument panel allow a front seat occupant to operate the heating and ventilation. These knobs are in the control, in the center of the instrument panel, just above or below the radio, depending on the vehicle. To the left of the blower motor speed control knob is the control button for the electric rear window defogger.
The controls are lit when the headlamps are on. Electrical power is provided by the instrument panel lighting circuit. The control lamp is in parallel with the instrument cluster bulbs, the radio dial bulb and certain other interior illumination bulbs. Brightness of the dial illumination is controlled by the dimmer control of the headlamp switch.

Temperature Control Knob

The temperature control knob is the middle knob in the control. It regulates the temperature of the air being discharged into the passenger compartment from the heater or ventilation system. The temperature control knob controls the position of a "door" called the temperature valve in the heater module. The temperature valve governs the relative amounts of heated and unheated air discharged from the heater system. Full warm, full cool or any intermediate temperature mixture can be selected by moving the knob to the right (red area) for warm air and to the left (blue area) for cool air or anywhere in between.

Mode Control Knob

The right knob, called the mode control knob, is a rotary vacuum switch that regulates airflow from the outlets by routing engine vacuum to vacuum actuators at the heater module. The mode control knob also controls an electrical switch that supplies power to operate the blower motor for specific mode selections.
A choice of six operating modes can be selected by turning the mode control knob in the control. From left to right, the six modes are "OFF", Vent, Bi-level, Heater, Blend and Defrost.

Blower Motor Speed Control Knob

With the ignition switch in the "RUN" position, the blower motor flits in all mode control knob positions except "OFF" " Blower motor speed is controlled by a four-position electrical blower switch at the left side of the control. The blower switch provides a choice of low blower motor Speed, two medium blower motor speeds and a high blower motor speed

The circuit to the blower motor is completed to ground at the instrument panel through the instrument panel wiring harness.