Operation CHARM: Car repair manuals for everyone.

Heater-A/C Controls

HEATER AND AIR CONDITIONER CONTROL

Both the heater-only and heater-A/C systems use a combination of electrical and vacuum controls. These controls provide the vehicle operator with a number of setting options to help control the climate and comfort within the vehicle. Refer to the owner's manual in the vehicle glove box for more information on the features, use, and suggested operation of these controls.

The heater-only or heater-A/C control is located to the right of the instrument cluster and below the radio on the instrument panel. The control panel contains a rotary-type temperature control knob, a rotary-type mode control switch knob, and a rotary-type blower motor speed switch knob. Models with the optional rear heater-A/C unit have a rotary-type rear blower motor speed switch mounted in the accessory switch plate, which is located to the right of the heater-A/C control on the instrument panel.

Models with the optional rear heater-A/C unit also have an additional momentary electrical switch that is located within the heater-A/C control. This switch is operated by a cam mechanism that is driven by the temperature control knob. The switch opens and closes a circuit to ground in order to signal the rear mode control motor to change modes. The rear mode control motor controls the rear heat-A/C mode door and the rear water valve. When the temperature control knob is moved to at least 80 percent of its travel from the full counterclockwise (Cool) position, the rear heater-A/C unit is switched to the heat mode and the rear water valve is opened; and, when the temperature control knob is moved to at least 80 percent of its travel from the full clockwise (Warm) position, the rear heater-A/C unit is switched to the A/C mode and the rear water valve is closed.

The heater-A/C control unit cannot be repaired. If faulty or damaged, the entire unit must be replaced. The incandescent illumination lamps are available for service replacement.