| 412-00 Climate Control System - General Information | 2013 - 2014 Fusion |
| Description and Operation | Procedure revision date: 07/10/2013 |
System Operation
System Diagram
Network Message Chart
Module Network Input Messages APIM
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Climate control button status | FCIM | This message contains the climate control button status. |
Module Network Input Messages FCIM
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Ambient air temperature | PCM | This message contains raw value from the ambient air temperature sensor. |
| Climate control requests | APIM | This message contains both the climate control system voice commands as well as all climate control system touch screen inputs. |
| A/C clutch status | PCM | This message contains the status of the A/C compressor clutch. |
Module Network Input Messages PCM
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| HVAC A/C request | FCIM | This message requests the A/C compressor to be engaged. |
| Evaporator temperature | FCIM | This message contains the evaporator temperature. The PCM uses the evaporator temperature to determine the A/C compressor output. |
The Refrigerant Cycle
NOTE: HEV shown, others similar.
| Item | Description |
|---|---|
| 1 | Condenser outlet line |
| 2 | A/C pressure transducer |
| 3 | A/C compressor |
| 4 | A/C compressor outlet line |
| 5 | Evaporator inlet and outlet manifold |
| 6 | Evaporator |
| 7 | Thermostatic Expansion Valve (TXV) |
| 8 | A/C charge valve port (low side) |
| 9 | A/C charge valve port (high side) |
| 10 | A/C compressor inlet line |
| 11 | Condenser |
| 12 | Receiver drier element |
| 13 | High pressure vapor |
| 14 | High pressure liquid |
| 15 | Low pressure vapor |
| 16 | Low pressure liquid |
During stabilized conditions ( A/C system shutdown), the refrigerant pressures are equal throughout the system. When the A/C compressor is in operation, it increases refrigerant vapor pressure, raising its temperature. The high-pressure and high-temperature vapor is then released into the top of the A/C condenser.
The A/C condenser, being close to ambient temperature, causes the refrigerant vapor to condense into a liquid when heat is removed from the refrigerant by ambient air passing over the fins and tubing. The now liquid refrigerant, still at high pressure, exits from the bottom of the A/C condenser and enters the inlet side of the A/C receiver drier (integral to the condenser). The receiver drier is designed to remove moisture from the refrigerant system.
The outlet of the receiver drier is connected to the Thermostatic Expansion Valve (TXV). The Thermostatic Expansion Valve (TXV) provides the orifice, restricting refrigerant flow and separating the high and low pressure sides of the A/C system. As the liquid refrigerant passes across this restriction, its pressure and boiling point are reduced.
The liquid refrigerant is now at its lowest pressure and temperature. As it passes through the A/C evaporator, it absorbs heat from the airflow passing over the plate/fin sections of the A/C evaporator. This addition of heat causes the refrigerant to boil (convert to gas). The now cooler air can no longer support the same humidity level of the warmer air and the excess moisture condenses on the exterior of the evaporator coils and fins and drains outside the vehicle.
The refrigerant cycle is now repeated with the A/C compressor again increasing the pressure and temperature of the refrigerant.
The PCM monitors the evaporator temperature sensor thermistor as air is passed through the evaporator core and controls the A/C clutch relay. If the temperature of the evaporator core is low enough to cause the condensed water vapor to freeze, the A/C clutch is disengaged by the PCM .
The high-side line pressure is monitored so that A/C compressor operation is interrupted if the system pressure becomes too high or too low (low charge condition).
The A/C compressor relief valve opens and vents refrigerant to relieve unusually high system pressure.
Control System Logic
The climate control system controls are in one or more locations depending on vehicle option content:
When the FDIM touchscreen or voice commands are used and A/C is selected, the APIM sends a function request message over the Infotainment Controller Area Network (I-CAN) to the IPC . The IPC relays the requests to the GWM and the FCIM over the Medium Speed Controller Area Network (MS-CAN). The GWM sends the requests to the PCM over the High Speed Controller Area Network (HS-CAN)1. The PCM controls the A/C clutch relay.
When the customer directly inputs an A/C request into the FCIM , the module sends the request to the GWM over the Medium Speed Controller Area Network (MS-CAN). The GWM sends the request to the PCM over the High Speed Controller Area Network (HS-CAN)1. The PCM controls the A/C clutch relay.
The FCIM Programmable Module Installation (PMI) when it is replaced.
Controls and Compressor Operation
When an A/C request is received by the PCM , the PCM engages the A/C clutch relay when all of the following conditions are met:
The PCM monitors the discharge pressure measured by the A/C pressure transducer. The PCM interrupts A/C compressor operation in the event 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 does not allow the A/C clutch to engage.
The FCIM adjusts the air inlet door depending on the humidity measured by the in-vehicle temperature and humidity sensor. If the vehicle cabin becomes too humid and recirculated air is selected, the FCIM adjusts the air inlet door to allow more fresh air. When the humidity level drops, it may adjust back to partial recirculated air. The FCIM also adjusts the system based on in-vehicle temperature.
The sunload sensor supplies information to the FCIM indicating the intensity of the sun on the vehicle. The FCIM adjusts the system based on the intensity.
Heating and Ventilation
The heating and ventilation system:
Vehicles equipped with Auto Start-Stop have a cabin heater coolant pump.
Air Handling
There are 4 door actuators that control the air flow into the passenger compartment:
All of the door actuators contain a reversible electric motor and a potentiometer. The potentiometer circuit consists of a 5-volt reference signal connected to one end of a variable resistor, and a signal ground connected to the other. A signal circuit is connected to a contact wiper, which is driven along the variable resistor by the actuator shaft. The signal to the FCIM from the contact wiper indicates the position of the actuator door. The FCIM powers the actuator motors to move the doors to the desired positions. The desired door positions are calculated by the FCIM based on the set temperature, in-vehicle temperature, ambient air temperature and sunload.
When an airflow mode, desired driver or passenger temperature, fresh air, or recirculation mode is selected, the FCIM moves the actuator motor in the desired direction.
The FCIM sends a PWM signal to the blower motor speed control to regulate the blower speed as necessary. The blower motor speed control provides variable ground feed for the blower motor based on the input from the FCIM . A delay function provides a gradual increase or decrease in blower motor speed under all conditions.
AUTO
When AUTO is selected:
OFF
When OFF is selected:
MAX AC
When MAX A/C is selected:
PANEL
When PANEL mode is selected:
PANEL-FLOOR
When PANEL/FLOOR mode is selected:
FLOOR
When FLOOR mode is selected:
FLOOR-DEFROST
When FLOOR/DEFROST mode is selected:
MAX DEFROST
When MAX DEFROST mode is selected:
MyTemp
The MyTemp feature can be used to store and recall a preset driver's temperature. This feature is provided so this temperature can be quickly adjusted to a frequently used setting with a single button press. For additional information about MyTemp, refer to the Owner's Literature.
Remote Start - Message Center Set To Auto
Remote start is an optional feature available on this vehicle. In addition to being able to start the vehicle remotely, the remote start feature also utilizes other vehicle systems to increase the level of comfort to the vehicle occupants upon entering the vehicle. Additional information on the remote start feature and the other vehicle systems, refer to Owner's Literature.
Set the climate control to operate in Auto mode through the information display setting: Remote Start > Climate Control > Heater–A/C > Auto, refer to the Owner's Literature for more information.
When the factory remote start feature is used, the Dual Automatic Temperature Control (DATC) system automatically sets certain parameters in an attempt to achieve a comfortable cabin temperature. These parameters are set based on outside air temperature. During remote start, the outside air temperature is continually evaluated and HVAC system behavior can change if the outside air changes between cold, moderate and warm temperatures.
For cold ambient air temperatures as determined by the FCIM AUTO mode to request heat:
For moderate and warm ambient air temperatures as determined by the FCIM AUTO mode to request heat or cooling:
Remote Start - Message Center Set To Last User Settings
Remote start is an optional feature available on this vehicle. In addition to being able to start the vehicle remotely, the remote start feature also utilizes other vehicle systems to increase the level of comfort to the vehicle occupants upon entering the vehicle. Additional information on the remote start feature and the other vehicle systems, refer to Owner's Literature.
Set the climate control to operate using the last climate control settings through the information display setting: Remote Start > Climate Control > Heater–A/C > Last Settings, refer to the Owner's Literature for more information.
When the factory remote start feature is used and the IPC message center is set to last user settings, the Dual Automatic Temperature Control (DATC) system automatically sets certain parameters in an attempt to achieve a comfortable cabin temperature. These parameters are set based on outside air temperature. During remote start, the outside air temperature is continually evaluated and HVAC system behavior can change if the outside air changes between cold, moderate and warm temperatures.
For cold ambient air temperatures as determined by the FCIM AUTO mode to request heat:
For moderate and warm ambient air temperatures as determined by the FCIM AUTO mode to request heat or cooling:
Component Description
FCIM - Dual Automatic Temperature Control (DATC)
The Dual Automatic Temperature Control (DATC) system uses the FCIM as the HVAC control module. The FCIM also controls the outputs for rear window defrost and climate controlled seats. For vehicles equipped with touchscreen audio, the Dual Automatic Temperature Control (DATC) system uses voice commands or the touchscreen to control the system. For details on the FCIM communication, refer to Control System Logic in this section.
The FCIM utilizes a Field-Effect Transistor (FET) protective circuit strategy for its actuator outputs. Output load (current level) is monitored for excessive current (typically short circuits) and is shut down (turns off the voltage or ground provided by the module) when a fault event is detected. A short circuit DTC is stored at the fault event and a cumulative counter is started.
When the demand for the output is no longer present, the module resets the Field-Effect Transistor (FET) circuit protection to allow the circuit to function. The next time the driver requests a circuit to activate that has been shut down by a previous short (Field-Effect Transistor (FET) protection) and the circuit is still shorted, the Field-Effect Transistor (FET) protection shuts off the circuit again and the cumulative counter advances.
When the excessive circuit load occurs often enough, the module shuts down the output until a repair procedure is carried out. The Field-Effect Transistor (FET) protected circuit has 3 predefined levels of short circuit tolerance based on the harmful effect of each circuit fault on the Field-Effect Transistor (FET) and the ability of the Field-Effect Transistor (FET) to withstand it. A module lifetime level of fault events is established based upon the durability of the Field-Effect Transistor (FET). If the total tolerance level is determined to be 600 fault events, the 3 predefined levels would be 200, 400 and 600 fault events.
When each tolerance level is reached, the short circuit DTC that was stored on the first failure cannot be cleared by a command to clear the Diagnostic Trouble Codes (DTCs). The module does not allow the DTC to be cleared or the circuit to be restored to normal operation until a successful self-test proves that the fault has been repaired. After the self-test has successfully completed (no on-demand Diagnostic Trouble Codes (DTCs) present), DTC U1000:00 and the associated DTC (the DTC related to the shorted circuit) automatically clears and the circuit function returns.
When each level is reached, the DTC associated with the short circuit sets along with DTC U1000:00. These Diagnostic Trouble Codes (DTCs) can be cleared using the module self-test, then the Clear DTC operation on the scan tool. The module never resets the fault event counter to zero and continues to advance the fault event counter as short circuit fault events occur.
If the number of short circuit fault events reach the third level, then Diagnostic Trouble Codes (DTCs) U1000:00 and U3000:49 set along with the associated short circuit DTC . DTC U3000:49 cannot be cleared and a new module must be installed after the repair.
The FCIM requires Programmable Module Installation (PMI) when it is replaced.
Cabin Heater Coolant Pump - vehicles equipped with Auto Start-Stop
The cabin heater coolant pump is available on vehicles equipped with Auto Start-Stop feature only. The cabin heater coolant pump provides coolant to the heater core whenever the HVAC system requests heat and the vehicle is in Auto Start-Stop mode. Refer to the Owner's Literature, Unique Driving Characteristics, for full Auto Start-Stop enabling/disabling information.
The PCM sends a PWM signal to the cabin heater coolant pump based upon the:
Blower Motor
The blower motor pulls air from the air inlet and forces it into the heater core and evaporator core housing and the plenum chamber where it is mixed and distributed.
Blower Motor Speed Control
The blower motor speed control uses a PWM signal from the FCIM to determine the desired blower speed and varies the ground feed for the blower motor to control the speed.
Evaporator Core
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 through the evaporator inlet tube and continues out of the evaporator through the evaporator 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 fins.
Heater Core
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.
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 door(s). After passing through the heater core, the airflow is distributed to the selected outlet by the airflow mode doors.
Air Distribution Door Actuator
The air distribution door actuator contains a reversible electric motor and a potentiometer. The potentiometer allows the FCIM to monitor the position of the airflow mode door.
Air Inlet Door Actuator
The air inlet door actuator contains a reversible electric motor and a potentiometer. The potentiometer allows the FCIM to monitor the position of the airflow mode door. The FCIM drives the actuator motor in the direction necessary to move the door to the position set by the recirculation button and the in-vehicle temperature and humidity sensor information.
Driver Side Temperature Door Actuator
The driver side temperature door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the FCIM to monitor the position of the temperature blend door.
Passenger Side Temperature Door Actuator
The passenger side temperature door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the FCIM to monitor the position of the temperature blend door.
Air Conditioning (A/C) Pressure Transducer
The PCM monitors the discharge pressure measured by the A/C pressure transducer. As the refrigerant pressure changes, the resistance of the A/C pressure transducer changes. It is not necessary to recover the refrigerant before removing the A/C pressure transducer.
In-Vehicle Temperature And Humidity Sensor
The in-vehicle temperature and humidity sensor contains a thermistor and a sensing element which separately measures the in-vehicle air temperature and the humidity, then sends those readings to the FCIM . The in-vehicle temperature and humidity sensor has an electric fan within the sensor that draws in-vehicle air across the two sensing elements. The FCIM may adjust the air inlet door based on the in-vehicle temperature and humidity sensor information to maintain the desired humidity of the passenger cabin air.
Sunload Sensor
The sunload sensor supplies information to the FCIM indicating the intensity of the sun on the vehicle. The FCIM compensates high sun load with higher blower and reduced discharge temperatures.
Evaporator Temperature Sensor
The evaporator temperature sensor contains a thermistor. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises. The evaporator temperature sensor is an input to the FCIM and the information is relayed to the PCM over the CAN . If the temperature is below a predetermined value, the PCM does not allow the A/C compressor to operate.
Air Discharge Temperature Sensors
There are 4 air discharge temperature sensors in the Dual Automatic Temperature Control (DATC) system:
All 4 air discharge temperature sensors contain a thermistor and are inputs to the FCIM . The sensors vary their resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises. The FCIM uses the sensor information to maintain the desired temperature of the passenger cabin air.
Internal Heat Exchanger (IHX)
The evaporator inlet and outlet manifold incorporates the Internal Heat Exchanger (IHX) and is serviced as an assembly. The Internal Heat Exchanger (IHX) combines a section of the A/C suction and liquid refrigerant lines into one component. It uses the cold vapor from the evaporator to cool the hot liquid from the condenser before it enters the Thermostatic Expansion Valve (TXV). After the Thermostatic Expansion Valve (TXV), more liquid refrigerant is available for absorbing heat in the evaporator. The result is an increase in cooling and operating efficiency of the HVAC system.
Externally Controlled Variable Displacement A/C Compressor
The externally controlled variable displacement compressor has:
Variable displacement compressors have a swash plate that rotates to reciprocate pistons, which compresses refrigerant. Variable displacement compressors change the swash plate angle to change the refrigerant displacement. The externally controlled variable displacement compressor changes the swash plate angle in accordance with an electrical signal from the PCM . Externally controlled variable displacement compressor manages displacement by controlling refrigerant differential pressure before and after a throttle at the discharge side; achieving precise cooling capability control in accordance with cabin environment and driving conditions.
The PCM sends a PWM signal to the solenoid in the compressor to control the compressor displacement based upon the:
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 refrigerant flow 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.
Condenser
The A/C condenser is an aluminum fin-and-tube design heat exchanger. 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. The receiver drier is integral to the A/C condenser.
Integrated Receiver Drier
The integrated receiver drier stores high-pressure liquid and the desiccant bag mounted inside the receiver drier removes any retained moisture from the refrigerant.
The receiver drier element is incorporated onto the LH side of the A/C condenser. The receiver drier element can be separately removed and installed with the A/C condenser in the vehicle.
Service Gauge Port Valves
| Item | Torque | Description |
|---|---|---|
| 1 | 0.8 Nm (7 lb-in) | Low-pressure service gauge port valve cap |
| 2 | — | Low-pressure service gauge port valve |
| 3 | 2.26 Nm (20 lb-in) | Low-pressure Schrader-type valve |
| 4 | 3.4 Nm (30 lb-in) | High-pressure Schrader-type valve |
| 5 | — | High-pressure service gauge port valve |
| 6 | 0.8 Nm (7 lb-in) | High-pressure service gauge port valve cap |
The service gauge port fitting is an integral part of the refrigerant line or component.
Refrigerant System Dye
A fluorescent refrigerant system dye wafer is added to the receiver drier desiccant bag to assist in refrigerant system leak diagnosis using a Rotunda-approved UV blacklight. This fluorescent dye wafer dissolves after about 30 minutes of continuous A/C operation. It is not necessary to add additional dye to the refrigerant system before diagnosing leaks, even if a significant amount of refrigerant oil has been removed from the system.
Copyright © Ford Motor Company