Manual Climate Control

MANUAL CLIMATE CONTROL

Component Locations - Manual Climate Control, Part 1:

Component Locations - Manual Climate Control, Part 2:

The manual climate control system heats or cools the vehicle interior depending on the function selector position and the temperature selected. The function selector position determines heating or cooling and air distribution. The temperature blend control setting determines air temperature.

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

Manual Climate 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 (B+) to the blower motor control circuit and the A/C clutch circuit (if equipped).
- The temperature selection is accomplished with a potentiometer connected to the electric 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.

Manual Climate Control System Outputs

Blower Motor Resistor Coils:

Blower Motor Thermal Limiter:

Blower Motor Switch Resistor

The heater blower motor switch resistor has the following features:
- The assembly is located on the evaporator core housing in the engine compartment.
- Three resistance elements are mounted on the resistor board to provide four A/C blower motor speeds.
- Depending on the heater blower motor switch position, series resistance is added or bypassed in the A/C blower motor circuit to decrease or increase A/C 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 repairable.

Temperature Blend Door Actuator
The temperature blend door actuator:
- is located on the top of the plenum chamber behind the glove compartment.
- moves the temperature blend door on command from the temperature control switch.

Vacuum Control Motors
The two vacuum control motors:
- are actuated by vacuum from the function selector switch.
- position the plenum doors to direct system airflow to the vehicle's interior as determined by the function selector switch setting.