HVAC Climate Control System: Other Ford Focus II рестайлинг

MATERIAL

MATERIAL

Air Conditioning

The refrigerant system components include the following

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

The refrigerant system incorporates an A/C compressor controlled by the PCM through an A/C clutch relay. The HVAC module sends an A/C request signal to the instrument cluster, which relays the request to the PCM. An evaporator discharge air temperature sensor is used to cycle the A/C compressor off when the evaporator core temperature falls below an acceptable temperature.

The HVAC module will send an A/C request signal to the instrument cluster if the following conditions are met

1. A mode which requires A/C operation has been manually selected by the driver.
2. The A/C evaporator discharge air temperature sensor is reading an acceptable temperature.

When an A/C request is received, the A/C compressor clutch will only be engaged by the PCM through the A/C clutch relay if all of the following conditions are met

1. The A/C pressure transducer is reading an acceptable pressure in the high-pressure side of the refrigerant system.
2. The engine coolant temperature is not excessively high.
3. The PCM has not detected a wide open throttle (WOT) condition.

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

A/C Pressure Relief Valve

Note. If the A/C compressor is operating within limits and the A/C pressure relief valve is venting, or if the A/C pressure relief valve is leaking around the threads, install a new A/C pressure relief valve and O-ring. If the new A/C pressure relief valve still vents after it is installed, diagnose the refrigerant system for a restriction.

An A/C pressure relief valve is incorporated in the A/C compressor to prevent damage to the A/C compressor and other system components by relieving unusually high system discharge pressure buildups. For specifications regarding operating pressure(s), refer to CLIMATE CONTROL SYSTEM - GENERAL INFORMATION AND DIAGNOSTICS .

The A/C pressure relief valve is a separate component and can be installed separately from the A/C compressor. It is necessary to recover the refrigerant before removing the A/C pressure relief valve.

A/C Condenser Core

The A/C 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 condenses gas to liquid refrigerant as it is cooled.

A/C Evaporator Core

Note. The evaporator core is not separately serviceable, it is serviced only with the evaporator core housing assembly.

The evaporator core is an aluminum plate/fin type and is located in the heater core and evaporator core housing. A mixture of liquid 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 as a vapor. During A/C compressor operation, airflow from the blower motor is cooled and dehumidified as it flows through the evaporator core fins.

Thermostatic Expansion Valve (TXV)

The thermostatic expansion valve (TXV) is located at the evaporator core inlet and outlet tubes at the center 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 A/C system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the receiver/drier. Damage to the receiver/drier includes leaks, physical damage to the receiver/drier shell or desiccant, or moisture contamination. Moisture contamination results only from a complete loss of refrigerant, and equalization of the refrigerant system pressure with atmospheric pressure for a period longer than one hour. If even a slight amount of positive refrigerant pressure is present in the refrigerant system before repairs are carried out, a new receiver/drier should not be installed.

The receiver/drier is mounted to the LH front of the condenser core. It stores high-pressure liquid after it leaves the condenser core. A desiccant cartridge mounted inside the receiver/drier removes moisture from the refrigerant.

A/C Evaporator Discharge Air Temperature Sensor

The A/C evaporator discharge air temperature sensor contains a thermistor which receives a reference voltage from the HVAC module. The thermistor then varies the resistance to the reference voltage based on the evaporator discharge air temperature. The HVAC module interprets this resistance as the evaporator discharge air temperature.

The A/C evaporator discharge air temperature sensor is located on the RH side of the heater core and evaporator core housing above the heater core tube cover.

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.

The A/C pressure transducer is located on the condenser-to-evaporator line near the RH shock tower. It is not necessary to recover the refrigerant before removing the A/C pressure transducer.

Service Gauge Port Valves

The high-pressure service gauge port valve is located on a vertical extension off the receiver/drier tank. The valve can be accessed through an access hole in the upper radiator air deflector to the right of the LH headlamp.

The low-pressure service gauge port valve is located on the A/C compressor suction line near the RH shock tower.

Scheme 13

The fitting is an integral part of the refrigerant system 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 each include an O-ring seal which is used as a primary seal in the refrigerant system to prevent leakage through the Schrader-type valves from reaching the atmosphere. The service gauge port valve cap O-ring seals should be checked when checking the refrigerant system for leaks and a new cap should be installed if needed. 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 black light. 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% of the refrigerant system lubricant capacity has been lost due to a fitting separation or hose rupture. Refer to CLIMATE CONTROL SYSTEM - GENERAL INFORMATION AND DIAGNOSTICS .

Air Distribution and Filtering

Note. The air distribution system is not designed for use with a cabin air filter. A cabin air filter is not installed from the factory and is not available as a dealer installed accessory.

Note. The temperature blend door and airflow mode doors are positioned by electric actuators. No vacuum-operated components are used in the climate control system.

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 HVAC module is set to the MAX A/C mode and can be selected in any mode except DEFROST.

Air distribution within the vehicle is determined by the airflow mode selected. Electric actuator controlled airflow mode control doors are used to direct airflow within the air inlet duct and plenum chamber. Electric mode door actuators are used to position the airflow mode doors.

Air enters the passenger compartment from the following outlets

1. Instrument panel registers
2. Floor duct outlets
3. Windshield defroster
4. Side window demisters
5. Rear footwell duct

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

Electronic Manual Temperature Control (EMTC)

The HVAC module allows the vehicle occupants to select the following

1. Air inlet source (outside or recirculated)
2. Blower motor speed
3. Discharge air temperature (temperature blend)
4. Discharge air location (defrost, panel, floor, panel/floor, defrost/floor)
5. A/C compressor operation
6. Rear window defroster operation
7. Heated seat operation (if equipped)

Control System Inputs

The blower motor speed switch is mounted in the HVAC module and controls blower motor speed by adding or bypassing resistors in the blower motor resistor in all modes except OFF. The blower motor speed switch is serviced only as an assembly with the HVAC module.

The temperature control switch adjusts the discharge air temperature. Movement of the temperature knob from COOL (blue) to WARM (red) causes a corresponding movement of the temperature blend door. The position of the temperature blend door determines the discharge air temperature that the air distribution system will maintain. The temperature control selector is an integral part of the HVAC module and cannot be installed separately.

The airflow mode setting adjusts the discharge air outlet location. Depressing each airflow mode selector button causes a corresponding movement of the airflow mode doors and determines the discharge air outlet location. The airflow mode selector buttons are each an integral part of the HVAC module and cannot be installed separately.

The A/C request button determines A/C compressor operation, except when the airflow mode selector is in the OFF, MAX A/C or DEFROST mode. The A/C request button is an integral part of the HVAC module and cannot be installed separately.

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 recirculated air request button is an integral part of the HVAC module and cannot be installed separately.

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

Control System Outputs

The electronic manual temperature control (EMTC) system has 4 system outputs.

Blower Motor Speed

The blower motor speed switch varies the blower motor ground circuit resistance by adding or bypassing series resistance in the blower motor resistor. Increased resistance will lower the blower motor speed, and lowered resistance will increase blower motor speed. When the blower motor is in the HI (4) position, the blower motor resistor is bypassed.

The blower motor resistor is located on the heater core and evaporator core housing behind the glove compartment.

Temperature Blend Door Position

The temperature blend door actuator moves the temperature blend door on command from the HVAC module.

The temperature blend door actuator contains a reversible electric motor and a potentiometer. The potentiometer circuit reports the position of the temperature blend door to the HVAC module. The HVAC module drives the temperature blend door actuator motor in whichever direction is necessary to move the temperature blend door to the position set by the vehicle occupants.

The temperature blend door actuator is mounted to the heater core and evaporator core housing to the right of the accelerator pedal and can be installed separately.

Airflow Mode Door Position

The airflow mode door actuator uses a cam and lever assembly to position the airflow mode doors on command from the HVAC module.

The mode door actuator contains a reversible electric motor and potentiometer. The potentiometer circuit reports the position of the airflow mode doors to the HVAC module. The HVAC module drives the actuator motor in whichever direction is necessary to move the airflow mode doors to the position set by the vehicle occupants using the mode selector buttons.

The airflow mode door actuator is mounted to the plenum chamber to the right of and above the accelerator pedal and can be installed separately.

Air Inlet Mode Door Position

The air inlet mode door actuator moves the air inlet door between the fresh and RECIRC positions on command from the HVAC module. The air inlet mode door actuator is driven to, and will automatically stop at, the full RECIRC or full fresh air inlet position and does not require a potentiometer circuit to monitor its position. The airflow mode door does not stop at any point between the RECIRC or fresh air inlet position.

The air inlet mode door actuator is mounted to the air inlet duct and can be accessed through the glove compartment. The air inlet mode door actuator can be installed separately.

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

The heating and ventilation system includes the following components

1. Blower motor
2. Heater core and evaporator core housing
3. Heater core

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. The blower motor receives battery voltage at all times when the ignition is in the RUN position, and is grounded by the blower motor switch.

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 an electric motor actuated temperature blend door. After passing through/around the heater core, the airflow is distributed to the selected outlet by 2 airflow mode doors. The 2 airflow mode doors are actuated by a single electric motor using a cam and gear setup.

Heater Core

The heater core receives a flow of coolant from the engine cooling system through the heater core inlet. The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core. The engine coolant is then returned to the engine cooling system through the heater core outlet.

Scheme 14

The heater core inlet and outlet tubes can each be separated from the heater core at the joints where they enter the core. The joints are each sealed using an O-ring seal, and are each secured with a clamp. It is not required to install new heater core inlet and outlet tubes when installing a new heater core unless they are damaged or are leaking independently from the core.

Air Conditioning (A/C) Compressor

MATERIAL - AIR CONDITIONING COMPRESSOR

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Air Conditioning (A/C) Pressure Relief Valve

MATERIAL - AIR CONDITIONING PRESSURE RELIEF VALVE

Scheme 16

Clutch and Clutch Field Coil

SPECIAL TOOLS - CLUTCH AND CLUTCH FIELD COIL Illustration Tool Name Tool Number Installer, A/C Clutch 412-136 Protector, A/C Compressor Shaft 412-137

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Compressor to Condenser Discharge Line

MATERIAL - COMPRESSOR TO CONDENSER DISCHARGE LINE

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Condenser Core

MATERIAL - CONDENSER CORE

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Condenser to Evaporator Line

MATERIAL - CONDENSER TO EVAPORATOR LINE

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Evaporator Outlet Line

MATERIAL - EVAPORATOR OUTLET LINE

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Evaporator to Compressor Suction Line

MATERIAL - EVAPORATOR TO COMPRESSOR SUCTION LINE

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MATERIAL - HEATER CORE AND EVAPORATOR CORE HOUSING

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Receiver Drier

MATERIAL - RECEIVER DRIER

Scheme 25

Thermostatic Expansion Valve

MATERIAL - THERMOSTATIC EXPANSION VALVE

Scheme 26