HVAC Control System: Other Ford Freestyle I

Air Conditioning

The climate control system components include the following

1. A/C compressor
2. A/C clutch assembly
3. A/C condenser core
4. A/C evaporator core
5. Receiver/drier
6. Connecting refrigerant lines
7. Thermostatic expansion valve

The refrigerant system incorporates an A/C compressor controlled by the powertrain control module (PCM) through an A/C clutch relay. The climate control assembly sends an A/C request signal to the instrument cluster module which relays the request to the PCM. An evaporator discharge air temperature sensor is used to disengage the A/C compressor clutch when the evaporator core temperature falls below 4°C (39°F).

The A/C compressor clutch will only be engaged by the PCM if all of the following conditions are met

1. The climate control assembly is set to a mode which provides an A/C request to the PCM via the instrument cluster module (ICM).
2. The evaporator discharge air temperature sensor is reading a temperature above 4°C (39°F).
3. The A/C pressure transducer is not reading a pressure above 2,841 kpa (412 psi) in the high side of the refrigerant system.
4. The A/C compressor relay is switched to the CLOSED position by the PCM.
5. The engine coolant temperature is not excessively high.
6. The PCM has not detected a wide open throttle (WOT) condition.

An A/C pressure relief valve is installed in the A/C manifold and tube to protect the refrigerant system against excessively high refrigerant pressures.

Refrigerant flow into the evaporator core is metered by a thermostatic expansion valve (TXV).

Condenser Core

Note. Installation of a new receiver/drier is not required when repairing the refrigerant system except when there is physical evidence of contamination from a failed A/C compressor or damage to the receiver/drier.

The condenser is an aluminum fin and tube design heat exchanger, located in front of the vehicle radiator. It cools compressed refrigerant gas by allowing air to pass over fins and tubes to extract heat and by condensing gas to liquid refrigerant as it is cooled.

Evaporator Core

Note. Installation of a new receiver/drier is not required when repairing the refrigerant system except when there is physical evidence of contamination from a failed A/C compressor or damage to the receiver/drier.

The evaporator core is an aluminum plate/fin type and is located in the heater core and evaporator core housing. A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and continues out of the evaporator core through the evaporator core outlet tube. Air from the blower motor is cooled and dehumidified as it flows through the evaporator core fins.

Thermostatic Expansion Valve

The TXV is located between the evaporator core lines and the thermostatic expansion valve manifold and tube assembly at the rear of the engine compartment. The TXV provides a restriction to the flow of refrigerant from the high-pressure side of the refrigerant system and separates the low-pressure and high-pressure sides of the refrigerant system. Refrigerant entering and exiting the evaporator core passes through the TXV through 2 separate flow paths. An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures and increases the amount of refrigerant entering the evaporator core at higher temperatures.

Receiver Drier

Note. Installation of a new receiver/drier is not required when repairing the refrigerant system except when there is physical evidence of contamination from a failed A/C compressor or damage to the receiver/drier.

The receiver/drier is mounted to the right of the radiator support. It stores high-pressure liquid after it leaves the condenser core. A desiccant bag mounted inside the receiver/drier removes any retained moisture from the refrigerant.

Evaporator Discharge Air Temperature Sensor

The evaporator discharge air temperature sensor contains a thermistor which receives a reference voltage from the PCM. The thermistor then varies the resistance to the reference voltage based on the evaporator discharge air temperature. The resulting voltage is returned to the PCM where it is interpreted as an evaporator air discharge temperature reading.

The PCM maintains evaporator core temperature and prevents icing of the evaporator core, by disengaging the A/C compressor clutch when the evaporator discharge air temperature sensor reading falls below 4°C (39°F), and by engaging the A/C compressor clutch when the discharge air temperature rises above 5°C (41°F).

The evaporator discharge air temperature sensor is located on the heater core and evaporator core housing in the air-stream leaving the evaporator core.

A/C Pressure Transducer

The A/C pressure transducer monitors the compressor discharge pressure and communicates with the PCM. The PCM will interrupt A/C compressor operation in the event that the A/C pressure transducer indicates high system discharge pressures. It is also used to sense low charge conditions. If the pressure is below a predetermined value for a given ambient temperature, the PCM will not allow the clutch to engage.

Peanut Fitting

Scheme 31

When disconnecting or connecting peanut fittings, observe the following

1. The male and female blocks of the peanut fitting are retained with a nut.
2. Support the female fitting with a wrench to prevent twisting of the tubes.
3. An O-ring seal is installed around the tube on the male block.
4. When correctly assembled, the male and female fittings should be flush.
5. Use only the O-ring seal listed in the Ford Master Parts Catalog.

Service Gauge Port Valves

The high-pressure service gauge port valve is located on the compressor manifold and tube assembly near the condenser fitting.

The low-pressure service gauge port valve is located on the evaporator-to-suction accumulator line near the evaporator fitting.

Scheme 32

The fitting is an integral part of the refrigeration line or component.

1. Special couplings are required for both the high-side and low-side service gauge ports.
2. A very small amount of leakage will always be detectable around the Schrader-type valve with the service gauge port valve cap removed, and is considered normal. A new Schrader-type valve core can be installed if the seal leaks excessively.
3. The service gauge port valve caps are used as primary seals in the refrigerant system to prevent leakage through the Schrader-type valves from reaching the atmosphere. Always install and tighten the A/C service gauge port valve caps to the correct torque after they are removed.

Refrigerant System Dye

Fluorescent refrigerant system dye is added to the refrigerant system at the factory to assist in refrigerant system leak diagnosis using a Rotunda approved ultraviolet blacklight. It is not necessary to add additional dye to the refrigerant system before diagnosing leaks, even if a significant amount of refrigerant has been removed from the system. Replacement receiver/driers are shipped with a fluorescent dye "wafer" included in the desiccant bag, which will dissolve after approximately 30 minutes of continued A/C operation. It is not necessary to add dye after flushing or filtering the refrigerant system because a new receiver/drier is installed as part of the flushing or filtering procedure. Additional refrigerant system dye should only be added if more than 50 percent of the refrigerant system lubricant capacity has been lost due to a fitting separation, hose rupture, etc. For additional information, refer to FLUORESCENT DYE LEAK DETECTION .

Air Distribution and Filtering

There are 2 sources of air available to the air distribution system

1. Outside air
2. Recirculated air

Recirculated air is always used when the climate control assembly is set to the MAX A/C mode on vehicles equipped with manual climate control. Vehicles equipped with dual-zone electronic automatic temperature control (EATC) use recirculated air only when the RECIRC function is selected in any mode other than DEFROST, or when required by the EATC module in the AUTOMATIC mode.

Air distribution within the vehicle is determined by the function selector position (manual A/C), or the dual-zone EATC system in the AUTOMATIC mode. The air distribution mode on vehicles equipped with dual-zone EATC can be overridden by the driver if desired. Airflow mode control doors are used to direct airflow within the heater core and evaporator core housing. Electric mode door actuators are used to position these airflow mode doors.

Vehicles equipped with dual-zone EATC use 2 separate temperature blend doors. This allows individual temperature settings to be selected for the RH and LH air outlets. The airflow mode doors are not partitioned for separate RH and LH airflow positions. Therefore, the airflow mode will always remain similar for the RH and LH sides of the vehicle regardless of the temperatures selected.

Air enters the passenger compartment from the

1. instrument panel registers.
2. floor duct.
3. windshield defroster.
4. side window demisters.
5. rear footwell duct (if equipped).

Passenger compartment air is exhausted from the vehicle through open windows or body air vents.

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 2 system control inputs.

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 3 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 3 resistor elements mounted on the resistor board to provide 4 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.

1. contains a reversible electric motor.
2. 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.
3. 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 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 3 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. Pulse width modulated (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. apply 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.

Heating and Ventilation

The heating and ventilation system has the following features

1. Controls the temperature and, during A/C operation, reduces the relative humidity of the air inside the vehicle.
2. Delivers heated or cooled air to maintain the vehicle interior temperature and comfort level.
3. Cooling or heating can be adjusted to maintain the desired temperature.
4. Uses a reheat method to provide conditioned auto the passenger compartment.
5. All airflow from the blower motor passes through the A/C evaporator core.
6. Temperature blending is controlled by the temperature blend door(s), which regulate(s) the amount of air that flows through and around the heater core, where it is then mixed and distributed.

Heater Core

The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer the heat to air passing through the plenum.

Auxiliary Coolant Flow Pump

Vehicles with auxiliary climate control are equipped with an auxiliary coolant flow pump. The auxiliary coolant flow pump is electrically driven and provides increased coolant flow to the front and rear heater cores. The auxiliary coolant flow pump is operational any time the ignition is in the RUN position.

Blower Motor

The blower motor pulls air from the air inlet and forces it into the heater core and evaporator core housing where it is mixed and distributed.

Heater Core and Evaporator Core Housing

The heater core and evaporator core housing directs airflow from the blower motor through the evaporator core and heater core. All airflow from the blower motor passes through the evaporator core. The airflow is then directed through or around the heater core by the temperature blend door(s). Vehicles equipped with dual-zone electronic automatic temperature control (EATC) use a partitioned heater core and evaporator core housing with 2 electric actuator-positioned temperature blend doors. This allows for separate temperatures to be selected for the driver and passenger sides of the passenger compartment. Manual systems use a single electric actuator-positioned temperature blend door to direct airflow through or around the heater core.

Air Conditioning (A/C) Compressor

MATERIAL

Scheme 33

Clutch and Clutch Field Coil

SPECIAL TOOL(S) Remover, Compressor Pulley 412-001 (T71P-19703-B) Holding Fixture, Compressor Clutch 412-103 (T95L-19703-AH) Installer, A/C Compressor Pulley 412-109 (T97P-19D786-A)

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MATERIAL

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1. Remove the A/C compressor. For additional information, refer to «AIR CONDITIONING (A/C) COMPRESSOR»(ref-255259-S19286703362007053000000) .
2. Remove the A/C clutch disc and hub nut. Hold the A/C clutch disc and hub with the special tool. Remove the nut.
3. Remove the A/C clutch disc and hub.
4. Remove the A/C compressor pulley snap ring.
5. Using the special tool, remove the A/C clutch pulley.
6. Remove the A/C clutch field coil snap ring.
7. Remove the A/C clutch field coil. Remove the bolt. Remove the thermal limiter and A/C clutch field coil.

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1. Visually inspect the A/C clutch disc and hub, A/C compressor pulley and A/C clutch field coil for damage. Inspect for physical damage including cracked or melted components or discoloration due to excessive heat. Inspect for excessive wear including grooving in the A/C clutch disc and hub or A/C compressor pulley that is more than fingernail depth. Inspect for roughness in the A/C compressor pulley bearing.
2. Clean the A/C clutch disc and hub, A/C compressor pulley and A/C clutch field coil mounting surfaces.
3. Apply a pea-sized drop of silicone sealant to the thermal limiter socket.
4. Install the A/C clutch field coil. Install the A/C clutch field coil. Install the thermal limiter. Tighten to 6 N.m (53 lb-in).
5. Install the A/C clutch field coil snap ring.
6. Install the A/C compressor pulley. Install the special tool. Install the A/C compressor pulley.
7. Install the A/C compressor pulley snap ring with the bevel side out.
8. Place one nominal thickness A/C clutch disc and hub spacer inside the clutch hub spline opening.
9. Install the A/C clutch disc and hub.
10. Install the A/C clutch disc and hub nut. Hold the A/C clutch disc and hub with the special tool. Tighten to 26 N.m (19 lb-ft).
11. Measure and adjust the clutch air gap by removing or adding A/C clutch disc and hub spacers.
12. Install the A/C compressor. For additional information, refer to «AIR CONDITIONING (A/C) COMPRESSOR»(ref-255259-S19286703362007053000000) .

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MATERIAL

MATERIAL

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MATERIAL

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