Control Components

CONTROL COMPONENTS
The manual climate control system heats or cools (if equipped with A/C) the vehicle interior depending on the function selector position and the temperature selected. Function selector position determines heating or cooling (if equipped with A/C) and air distribution. The temperature blend control setting determines air temperature.

The manual climate control components are used to:
- select air inlet source (outside or recirculated).
- select blower motor speed.
- select discharge air temperature (temperature blend).
- select discharge air location (defrost, panel, floor).
- select A/C compressor clutch operation (if equipped with A/C).

Component Locations, Part 1:

Component Locations, Part 2:

Control System Inputs

Climate Control Assembly
The climate control assembly has three system controls:
- The function selector switch combines a vacuum selector valve with two electrical switches to supply battery positive voltage to the A/C clutch circuit (if equipped with A/C) and the blower motor control circuit.
- The temperature selection is accomplished with a potentiometer connected to the electric temperature blend door actuator that controls positioning of the temperature blend door. Movement of the control knob from COOL (Blue) to WARM (Red) causes a corresponding movement on the air temperature control door and determines the temperature that the system will maintain.
- The blower motor switch controls blower motor speed by adding or bypassing resistors in the heater blower motor switch resistor.

Control System Outputs

Blower Motor Resistor Thermal Limiter:

Blower Switch Resistor
The blower motor resistor has the following features:
- The assembly is located on the passenger side of the vehicle on the evaporator housing.
- Three resistance elements are mounted on the resistor board to provide four blower motor speeds.
- Depending on the blower switch position, series resistance is added or bypassed in the blower motor circuit to decrease or increase blower motor speed.
- An overheating protective device (thermal limiter) will open the resistor coil circuit when the temperature reaches 121°C (250°F) interrupting the blower motor operation in all speeds except HI.
- The thermal limiter cannot be reset and is not serviceable.