The control assembly in the instrument panel contains three rotary control knobs: the blower speed knob, the mode selection knob, and the temperature adjustment knob. The instrument panel dimmer control controls the brightness of the dial illumination.
Temperature Rotary Knob
When the temperature rotary knob is in the full COLD or counter clockwise position, all of the air delivered by the ventilation system is unheated. When the temperature rotary control is in the full HOT or clockwise position, all of the air passing through the heater module is heated prior to discharge. Intermediate positions of the temperature rotary knob result in a mixture of heated and unheated air in order to provide more moderated air temperatures.
Mode Rotary Knob
The mode rotary knob operates the defrost control cable that moves to the left end of the heater module. This cable operates a crank lever and the shaft that controls the position of the an air valve in the heater module. The detents at 0 degrees, 90 degrees, and 180 degrees indicate the VENT position, the FLOOR position, and the DEFROST position. By placing the rotary control anywhere in between the two desired modes, the operator can blend the air delivery.
Blower Speed Control
The blower switch provides a choice of four blower speeds and the OFF position. The blower switch receives power through the HTR-A/C FUSE when the ignition is in the ON position. In the LO position, the circuit continues through the heater wiring harness to the two resistors in the resistor assembly near the blower motor.
When the blower switch is in a medium-speed position, the circuit continues through the heater wiring harness to the resistor assembly, but the circuit bypasses one of the two resistors. When the blower switch is in the HIGH position, the circuit continues through the heater wiring harness to the resistor assembly. The circuit bypasses both resistors in order to provide full power to the blower motor.
From the resistor assembly, the circuit moves to the blower motor terminal in order to operate the blower motor. A sheet metal ground wire that connects to a ground terminal on the cowl completes the blower motor circuit to the ground.
