HVAC System - Control Components Ford Five Hundred I

Electronic Manual Temperature Control

The electronic manual temperature control (EMTC) components are used to select

1. air inlet source (outside or recirculated).
2. blower motor speed.
3. discharge air temperature (temperature blend).
4. discharge air location (defrost, panel, floor).
5. A/C compressor operation.

Control System Inputs

The EMTC system has two system control inputs.

Climate Control Assembly (EMTC Module)

The climate control assembly integrates the temperature control, airflow mode selection, A/C request button, recirculated air request button and rear defog switch into a single unit.

The temperature control switch setting determines air temperature. Movement of the temperature display 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 climate control assembly and cannot be separately replaced.

The A/C request button determines A/C compressor operation, except when the function selected is in the OFF, MAX or DEFROST mode. The A/C request button is an integral part of the climate control assembly and cannot be separately replaced.

The recirculated air request button can select recirculated air in any mode except DEFROST, and fresh air in any mode except MAX A/C or OFF.

The rear defog button signals activation of the heated backlight. The rear defog button is an integral part of the climate control assembly and cannot be installed separately.

The EMTC module is not equipped with self-test capabilities.

Blower Motor Switch

The blower motor switch is mounted in the climate control assembly and controls blower motor speed by adding or bypassing resistors in the blower motor resistor in all modes except OFF.

Control System Outputs

The EMTC system has three system outputs.

Blower Motor Resistor

The blower motor resistor

1. is located on the heater core and evaporator core housing near the blower motor.
2. has three resistor elements mounted on the resistor board to provide four blower motor speeds.
3. 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.
4. has an overheating device (thermal limiter) that will open the resistor when the temperature reaches approximately 220°C (428°F), interrupting the blower motor operation in all speeds except high.
5. is serviced as an assembly. The thermal limiter cannot be reset and is not serviceable.

Temperature Blend Door Actuator

The temperature blend door actuator

1. is located on the heater core and evaporator core housing.
2. moves the temperature blend door on command from the EMTC module.
3. contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the temperature blend door.
4. applies a 5-volt signal to one end of the potentiometer and ground to the other. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the EMTC module and is matched with an expected wiper voltage value. The EMTC module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the expected EMTC module wiper voltage value.

Mode Door Actuator

The mode door actuator

1. uses a cam setup to direct system airflow to the vehicle interior as determined by the climate control assembly.
2. contains a reversible electric motor.
3. contains a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the mode door.
4. applies a 5-volt signal to one end of the potentiometer and ground to the other. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the EMTC module and is matched with an expected wiper voltage value. The EMTC module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the expected EMTC module wiper voltage value.

Air Inlet Mode Door Actuator

The air inlet mode door actuator

1. moves the air inlet door between the FRESH and RECIRC positions on command from the EMTC module.
2. contains a reversible electric motor.
3. automatically stops when it reaches the full FRESH or full RECIRC position and does not report its position back to the EMTC module.

Dual-Zone Electronic Automatic Temperature Control

The dual-zone electronic automatic temperature control (EATC) module analyzes input from the following major sources

1. temperature, airflow direction, blower, A/C and RECIRC selection (made by the vehicle occupants)
2. in-vehicle temperature sensor
3. ambient temperature sensor
4. solar radiation sensor
5. vehicle speed
6. engine coolant temperature

Using these inputs, the dual-zone EATC module determines the correct conditions for the following outputs

1. A/C compressor operation
2. blower speed
3. temperature blend door position
4. defrost/panel/floor door position
5. air inlet door position

The dual-zone EATC system has 4 control system inputs.

EATC Module

The dual-zone EATC module

1. is located in the instrument panel.
2. has a vacuum fluorescent display for displaying set temperature, airflow direction, blower speed and diagnostic trouble codes (DTCs).
3. utilizes an on-board diagnostic (OBD) feature to supply the technician with diagnostic trouble codes (DTCs). These DTCs direct the technician to the inoperative component.

In-Vehicle Temperature Sensor

The in-vehicle temperature sensor operates in the following manner

1. A thermistor in the in-vehicle temperature sensor measures air temperature inside the passenger compartment.
2. An aspirator hose and elbow is connected between the heater core and evaporator core housing and the in-vehicle temperature sensor.
3. The aspirator hose and elbow takes air from the heater core and evaporator core housing air stream to create a suction in the in-vehicle temperature sensor.
4. The suction draws in-vehicle air into the in-vehicle temperature sensor and across the thermistor.

Solar Radiation Sensor (Sunload Sensor)

The solar radiation sensor supplies information to the dual-zone EATC module indicating sunload.

Ambient Temperature Sensor

The ambient temperature sensor signal is received by the dual-zone EATC module and indicates the outside air temperature.

The dual-zone EATC system has three control system outputs.

Blower Motor Speed Control

The blower speed control

1. is located on the heater core and evaporator core housing near the blower motor.
2. PWM signals from the dual-zone EATC module to control a high-current, variable ground feed for the blower motor.
3. varies the blower motor speed and is controlled by the dual-zone EATC module software.
4. has a delay function to provide a gradual increase or decrease in blower motor speed under all conditions.

Temperature Blend Door Actuators

The temperature blend door actuators

1. are located on the heater core and evaporator core housing.
2. move the temperature blend doors on command from the dual-zone EATC module.
3. each contain a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the temperature blend doors.
4. applies a 5-volt signal to one end of the potentiometer and ground to the other. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the dual-zone EATC module and is matched with an expected wiper voltage value. The dual-zone EATC module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the expected dual-zone EATC module wiper voltage value.

The mode door actuator

1. uses a cam setup to position the 2 airflow mode doors to direct system airflow to the vehicle interior as determined by the dual-zone EATC module settings.
2. contains a reversible electric motor.
3. contains a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the mode door.
4. applies a 5-volt signal to one end of the potentiometer and ground to the other. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the dual-zone EATC module and is matched with an expected wiper voltage value. The dual-zone EATC module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the expected dual-zone EATC module wiper voltage value.

The air inlet mode door actuator

1. moves the air inlet door between the FRESH and RECIRC positions on command from the EMTC module.
2. contains a reversible electric motor.
3. automatically stops when it reaches the full FRESH or full RECIRC position and does not report its position back to the dual-zone module.

Refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION .

Scheme 38

1. Remove the instrument panel center finish panel. For additional information, refer to «INSTRUMENT PANEL AND CONSOLE»(/ford/five-hundred/i-2004-2007/remont/gauges-instrument-panels/#instrument-panel-and-console) .
2. Remove the 4 climate control assembly screws.
3. Remove the climate control assembly.
4. To install, reverse the removal procedure.

Scheme 39

1. Remove the lower radiator splash shield.
2. Disconnect the ambient air temperature sensor electrical connector.
3. Remove the ambient air temperature sensor nut.
4. Remove the ambient air temperature sensor.
5. To install, reverse the removal procedure.

Scheme 40

Scheme 41

1. Remove the instrument cluster finish panel. For additional information, refer to «INSTRUMENT PANEL AND CONSOLE»(/ford/five-hundred/i-2004-2007/remont/gauges-instrument-panels/#instrument-panel-and-console) .
2. Remove the 3 lower steering column cover screws.
3. Remove the lower steering column cover.
4. Remove the 3 lower steering column shroud screws.
5. Remove the lower steering column shroud.
6. Disconnect the in-vehicle temperature sensor electrical connector.
7. Remove the in-vehicle temperature sensor.
8. To install, reverse the removal procedure.

Scheme 42

1. Lower the glove compartment.
2. Remove the 3 RH temperature blend door actuator screws.
3. Disconnect the RH temperature blend door actuator electrical connector.
4. Remove the RH temperature blend door actuator.
5. To install, reverse the removal procedure.

Scheme 43

Note. The LH temperature blend door actuator can be accessed from below the LH side of the instrument panel.

1. Remove the 3 LH temperature blend door actuator screws.
2. Disconnect the LH temperature blend door actuator.
3. Remove the LH temperature blend door actuator.
4. To install, reverse the removal procedure.

Scheme 44

1. Remove the RH lower instrument panel insulator.
2. Disconnect the blower motor resistor electrical connector.
3. Remove the 2 blower motor resistor screws.
4. Remove the blower motor resistor.
5. To install, reverse the removal procedure.

Scheme 45

1. Remove the RH lower instrument panel insulator.
2. Disconnect the blower motor speed control electrical connector.
3. Remove the 2 blower motor speed control screws.
4. Remove the blower motor speed control.
5. To install, reverse the removal procedure.

Scheme 46

Note. The defrost/panel/floor mode door actuator can be accessed from below the LH side of the instrument panel.

Scheme 47

1. Remove the steering column cover.
2. Remove the 3 screws and the lower steering column shroud.
3. Remove the speed control deactivator switch. For additional information, refer to «SPEED CONTROL»(/ford/five-hundred/i-2004-2007/remont/cruise-control-systems/#speed-control-system) .
4. Detach the wire harness pin-type retainer.
5. Remove the 3 defrost/panel/floor mode door actuator screws.
6. Disconnect the defrost/panel/floor mode door actuator electrical connector.
7. Remove the defrost/panel/floor mode door actuator.
8. To install, reverse the removal procedure.

Scheme 48

1. Lower the glove compartment.
2. Disconnect the air inlet mode door actuator electrical connector.
3. Remove the air inlet mode door actuator.
4. To install, reverse the removal procedure.

See also:
• CLIMATE CONTROL SYSTEM-GENERAL INFORMATION
• INSTRUMENT PANEL AND CONSOLE
• SPEED CONTROL