2005 INFINITI FX35 air

AIR CONDITIONER CONTROL ATC-31
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Revision: 2005 July 2005 FX
TRANSMISSION DATA AND TRANSMISSION ORDER
Unified meter and A/C amp. data is transmitted consecutively to each of the door motors following the form
shown in figure below.
Start:
Initial compulsory signal sent to each of the door motors.
Address:
Data sent from the unified meter and A/C amp. are selected according to data-based decisions made by the
air mix door motor, mode door motor and intake door motor.
If the addresses are identical, the opening angle data and error check signals are received by the door motor
LCUs. The LCUs then make the appropriate error decision. If the opening angle data have no error, door con-
trol begins.
If an error exists, the received data are rejected and corrected data received. Finally, door control is based
upon the corrected opening angle data.
Opening Angle:
Data that shows the indicated door opening angle of each door motor.
Error Check:
Procedure by which sent and received data is checked for errors. Error data are then compiled. The error
check prevents corrupted data from being used by the air mix door motor, the mode door motor and the intake
door motor. Error data can be related to the following symptoms.

Malfunction of electrical frequency

Poor electrical connections

Signal leakage from transmission lines

Signal level fluctuation
RJIA1748E

ATC-32
AIR CONDITIONER CONTROL
Revision: 2005 July 2005 FX
Stop Signal:
At the end of each transmission, a stop operation, in-operation, or internal malfunction message is delivered to
the unified meter and A/C amp. This completes one data transmission and control cycle.
AIR MIX DOOR CONTROL (AUTOMATIC TEMPERATURE CONTROL)
The air mix door is automatically controlled so that in-vehicle temperature is maintained at a predetermined
value by the temperature setting, ambient temperature, in-vehicle temperature and amount of sunload.
FAN SPEED CONTROL
Blower speed is automatically controlled by the temperature setting, ambient temperature, in-vehicle tempera-
ture, intake temperature, amount of sunload and air mix door position.
With pressing AUTO switch, the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flow-
ing.
INTAKE DOOR CONTROL
The intake doors are automatically controlled by the temperature setting, ambient temperature, in-vehicle tem-
perature, intake temperature, amount of sunload and ON-OFF operation of the compressor.
OUTLET DOOR CONTROL
The outlet door is automatically controlled by the temperature setting, ambient temperature, in-vehicle temper-
ature, intake temperature and amount of sunload.
RJIA1749E

AIR CONDITIONER CONTROL ATC-33
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MAGNET CLUTCH CONTROL
When A/C switch or DEF switch is pressed, unified meter and A/C amp. inputs compressor ON signal to BCM.
BCM sends compressor ON signal to ECM, via CAN communication line.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sen-
sor signal, throttle angle, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to
IPDM E/R, via CAN communication line.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.
When sending compressor ON signal to IPDM E/R via CAN communication line, ECM simultaneously sends
compressor feedback signal to unified meter and A/C amp. via CAN communication line.
Unified meter and A/C amp., then, uses input compressor feedback signal to control air inlet.
SELF-DIAGNOSIS SYSTEM
The self-diagnosis system is built into the unified meter and A/C amp. to quickly locate the cause of symp-
toms.
RJIA1957E

ATC-34
AIR CONDITIONER CONTROL
Revision: 2005 July 2005 FX
Description of Control SystemAJS0014C
The control system consists of input sensors, switches, the unified meter and A/C amp. (microcomputer) and
outputs. The relationship of these components is shown in the figure below:
Control OperationAJS0014D
DISPLAY SCREEN
Displays the operational status of the system.
RJIA1958E
RJIA1959E

AIR CONDITIONER CONTROL ATC-35
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AUTO SWITCH

The compressor, intake doors, air mix doors, mode doors and blower speed are automatically controlled
so that the in-vehicle temperature will reach, and be maintained at the set temperature selected by the
operator.

When pressing AUTO switch, air inlet, air outlet, fan speed, and discharge air temperature are automati-
cally controlled.
TEMPERATURE SWITCH (POTENTIO TEMPERATURE CONTROL) (DRIVER SIDE)
The set temperature is increased or decreased with this dial.
TEMPERATURE SWITCH (POTENTIO TEMPERATURE CONTROL) (PASSENGER SIDE)

The set temperature is increased or decreased with this dial.

When the temperature switch is pressed, the dual switch indicator will automatically illuminate.
RECIRCULATION (REC) SWITCH

When REC switch is ON, REC switch indicator turns ON, and air inlet is fixed to REC.

When REC switch is ON and is pressed for approximately 1.5 seconds or longer, REC and FRE switch
indicators blink twice. Then, automatic control mode is entered. Inlet status is displayed even during auto-
matically controlled.

When FRE switch is turned ON, or when compressor is turned from ON to OFF, REC switch is automati-
cally turned OFF (fixed to FRE mode). REC mode can be re-entered by pressing REC switch again.

REC switch is not operated when DEF switch is turned ON, or at the D/F position.
FRESH (FRE) SWITCH

When FRE switch is ON, FRE switch indicator turns ON, and air inlet is fixed to FRE.

When FRE switch is ON and is pressed for approximately 1.5 seconds or longer, REC and FRE switch
indicators blink twice. Then, automatic control mode is entered. Inlet status is displayed even during auto-
matically controlled.

When REC switch is turned ON, FRE switch is automatically turned OFF (fixed to REC mode). FRE mode
can be re-entered by pressing FRE switch again.
DEFROSTER (DEF) SWITCH
Mode doors are set to the defrost position with this switch. Also, intake doors are set to the outside air position,
and compressor turns ON.
REAR WINDOW DEFOGGER SWITCH
When illumination is ON, rear window is defogged.
OFF SWITCH
Compressor and blower are OFF, the intake doors are set to the outside air position, and the mode doors are
set to the foot (75% foot and 25% defrost) position.
A/C SWITCH
Compressor is ON or OFF.
(Pressing the A/C switch when the AUTO switch is ON will turn off the A/C switch and compressor.)
MODE SWITCH
The air discharge outlets is controlled by this switch.
FAN SWITCH
The blower speed is manually controlled with this switch. Seven speeds are available for manual control (as
shown on the display screen).
DUAL SWITCH (WITH LEFT AND RIGHT VENTILATION TEMPERATURE SEPARATELY CON-
TROL SYSTEM)

When the DUAL switch indicator is illuminated, the driver-side outlet and passenger-side outlet, as well as
the setting temperature, can each be set independently.

When the DUAL switch indicator is not illuminated, the driver-side outlet and setting temperature is
applied to both sides.

ATC-36
AIR CONDITIONER CONTROL
Revision: 2005 July 2005 FX
Fail-safe FunctionAJS0014E

If a communication error exists between unified meter and A/C amp. and A/C and AV switch for 30 sec-
onds or longer, air conditioner is controlled under following conditions:
–Compressor: ON
–Air outlet: AUTO
–Air inlet: FRE (Fresh)
–Blower fan speed: AUTO
–Set temperature: Setting before communication error occurs

AIR CONDITIONER CONTROL ATC-37
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Discharge Air FlowAJS0014F
RJIA1960E

ATC-38
AIR CONDITIONER CONTROL
Revision: 2005 July 2005 FX
System DescriptionAJS0014G
SWITCHES AND THEIR CONTROL FUNCTION
RJIA1961E
RJIA1962E