Explorer Sport Trac 2WD V6-4.0L VIN K (2007)
Control Assembly: Description and Operation
Control Components
CONTROL COMPONENTS
MANUAL CLIMATE CONTROL
The manual climate control components are used to select:
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air inlet source (outside or recirculated).
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blower motor speed.
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discharge air temperature (temperature blend).
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discharge air location (defrost, panel, floor).
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A/C compressor operation.
Control System Inputs
The climate control assembly has 3 system control inputs.
Climate Control Assembly
The climate control assembly integrates the temperature control switch, A/C request button and rear defog switch into a single unit.
The temperature control switch setting determines air temperature. Temperature selection is accomplished with a potentiometer (temperature control
switch) connected to the temperature blend door actuator. Movement of the temperature control switch from COOL (blue) to WARM (red) causes a
corresponding movement of the temperature blend door and determines the air discharge temperature that the air distribution system will maintain.
The temperature control switch is an integral part of the manual climate control assembly and a new one cannot be separately installed.
The A/C request switch determines A/C compressor operation, except when the function selector switch is in the OFF, MAX, DEFROST or
FLOOR/DEFROST positions. The A/C request switch is an integral part of the manual climate control assembly and a new one cannot be separately
installed.
The rear defog button signals activation of the heated backlight and heated mirrors. The rear defog button is an integral part of the manual climate
control assembly and a new one cannot be separately installed.
Function Selector Switch
The function selector switch combines a vacuum selector valve that determines air distribution and an electrical switch to supply battery voltage to the
A/C compressor circuit and the blower motor circuit. When the function selector switch is in the MAX A/C, DEFROST or FLOOR/DEFROST
positions, the A/C compressor will be operational regardless of the A/C request switch status.
Blower Motor Switch
The blower motor switch controls blower motor speed by adding or bypassing resistors in the blower motor switch resistor in all function selector
switch positions except OFF.
Control System Outputs
The climate control system has 5 system outputs.
Blower Motor Resistor
The blower motor resistor has 3 resistor elements mounted on the resistor board to provide 4 blower motor speeds. Depending on the blower motor
switch position, series resistance is added or bypassed in the blower motor circuit to decrease or increase blower motor speed. The blower motor
resistor has an overheating device (thermal limiter) that opens the resistor coil when 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 is not serviceable.
Temperature Blend Door Actuator
The temperature blend door actuator moves the temperature blend door on command from the temperature control switch using a reversible electric
motor. The temperature blend door actuator contains an internal controller that will recognize the temperature control switch signal and drive the
temperature blend door to the desired position.
The temperature blend door actuator is located on the LH side of the heater core and evaporator core housing.
Vacuum Control Motors
The 4 vacuum control motors move the airflow mode doors to direct system airflow to the vehicle interior as determined by the function selector
switch. Vacuum control motors are used to control the:
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air inlet door.
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defrost mode door.
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panel mode door.
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floor mode door.
Heater Control Valve Vacuum Switch
