Control Components

CONTROL COMPONENTS

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

Climate Control System Inputs

Temperature Selector Cable Assembly
The temperature selector cable assembly moves the temperature blend door between the cool and warm positions using a 2-sided pull-pull type cable assembly. The temperature selector controls the cable movement. The cable assembly attaches to the airflow mode door/temperature blend door actuating assembly which transfers the cable movement to the temperature blend door.

Function Selector Cable Assembly
The function selector cable assembly moves the airflow mode doors to the desired position using a 2-sided pull-pull type cable assembly. The function selector controls the cable movement. The end of the cable assembly attaches to the airflow mode door/temperature blend door actuating assembly which transfers the cable movement to the 2 airflow mode doors.

An electrical switch is incorporated into the function selector to notify the A/C switch assembly if DEFROST or FLOOR/DEFROST is selected. When DEFROST or FLOOR/DEFROST is selected, the A/C switch assembly will disable the RECIRC request button and send an A/C request to the powertrain control module (PCM) regardless of the A/C request button indicator ON/OFF status.

Blower Motor Switch
The blower motor switch controls the blower motor speed and enables the A/C request button. When the blower is set to HI, the blower motor switch provides a direct ground for the blower motor, resulting in HI blower speed. When LO, MED LO or MED HI blower is selected the blower motor switch directs the blower motor ground through the blower motor resistor.

A/C Switch Assembly
The A/C switch assembly integrates the A/C request button, RECIRC request button and rear DEFOG button into a single assembly.

The A/C request button is enabled by the blower motor switch. The A/C switch assembly sends a reference signal to the blower motor switch. When the reference signal is grounded (blower motor switch turned ON) the A/C request button is enabled. The A/C request button is disabled when the blower motor switch is in the OFF position. When the A/C request button is activated (indicator ON), an A/C request signal is sent to the PCM. The A/C request button indicator can be toggled on and off when in the FLOOR/DEFROST or DEFROST mode, but an A/C request signal will be sent to the PCM regardless of the indicator status.

When the RECIRC request button is activated (indicator ON), the air inlet mode door actuator will drive to the recirculated air inlet position. When the RECIRC request button is deactivated (indicator OFF), the air inlet mode door actuator will drive to the fresh air inlet position. The RECIRC request button is disabled when in the FLOOR/DEFROST or DEFROST mode.

Climate Control System Outputs

Blower Motor Resistor
The blower motor resistor adjusts the blower motor speed based on the blower motor switch setting. The blower motor resistor contains 3 resistor coils in series. The end of each resistor coil is wired to a setting in the blower motor switch. Voltage is available at the blower motor at all times when the ignition is in the run position and then continues to the blower motor resistor. The blower motor switch will allow a path to ground with the addition of 1, 2 or 3 coils in the blower motor resistor to the circuit. When the blower motor switch is in the MED HI position, the blower motor switch will add a path to ground through 1 coil in the blower motor resistor. When the blower motor switch is in the MED LO position, the blower motor switch will add a path to ground through 2 coils (in series) in the blower motor resistor. When the blower motor switch is in the LO position, the blower motor switch will add a path to ground through 3 coils (in series) in the blower motor resistor. When the blower motor switch is in the HI position, the blower motor resistor is bypassed.

The blower motor resistor has an overheating device (thermal limiter) that will open the resistor coil if the temperature reaches approximately 184°C (363°F), interrupting the blower motor operation in all speeds except high. The thermal limiter cannot be reset, and a new blower resistor must be installed if open.

Air Inlet Mode Door Actuator
The air inlet mode door actuator is a reversible electric motor which moves the air inlet door, between the fresh and recirculated air inlets, on command from the RECIRC request button on the A/C switch assembly. When RECIRC is requested, the air inlet mode door actuator moves to the RECIRC position, allowing only recirculated air inlet. When RECIRC is deselected, the air inlet mode door actuator moves to the FRESH air inlet position, allowing only fresh air inlet.

Airflow Mode Door/Temperature Blend Door Actuating Assembly
The airflow mode door/temperature blend door actuating assembly transfers the movement of the temperature selector cable to the temperature blend door, and transfers the movement of the mode selector cable assembly to the 2 airflow mode doors. The airflow mode door/temperature blend door actuating assembly is mounted on the LH side of the heater core and evaporator core housing.