air condition INFINITI QX4 2005 Factory Owners Manual

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AIR CONDITIONER CONTROL
Revision: October 20052005 QX56
AIR CONDITIONER CONTROLPFP:27500
DescriptionEJS003X5
The front air control provides automatic regulation of the vehicle's interior temperature. The system is based
on the driver's and passenger's selected "set temperature", regardless of the outside temperature changes.
This is done by utilizing a microcomputer, also referred to as the front air control, which receives input signals
from the following six sensors:

Ambient sensor

In-vehicle sensor

Intake sensor

Optical sensor (providing one input for driver and one input for passenger side)

PBR (Position Balanced Resistor)

Vehicle speed sensor
The front air control uses these signals (including the set temperature) to automatically control:

Outlet air volume

Air temperature

Air distribution
The front air control also provides separate regulation of the vehicle's interior temperature for the rear passen-
ger area. The system is based on the temperature and rear blower settings selected from rear control
switches located on the front air control, or from the temperature and rear blower settings selected from rear
control switches on the rear air control, when the front air control switches are set to the rear position.
The front air control is used to select:

Outlet air volume

Air temperature/distribution
OperationEJS003X6
AIR MIX DOORS CONTROL
The air mix doors are 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.
BLOWER 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.
When AUTO switch is pressed, the blower motor starts to gradually increase air flow volume (if required).
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flow-
ing.
INTAKE DOOR CONTROL
The intake door is automatically controlled by the temperature setting, ambient temperature, in-vehicle tem-
perature, intake temperature, amount of sunload and by the ON-OFF operation of the compressor.
MODE DOOR CONTROL
The mode door is automatically controlled by the temperature setting, ambient temperature, in-vehicle temper-
ature, intake temperature and amount of sunload.
DEFROSTER DOOR CONTROL
The defroster door is controlled by: Turning the defroster dial to front defroster.

AIR CONDITIONER CONTROL
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MAGNET CLUTCH CONTROL
When A/C switch or DEF switch is pressed, front air control 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 sensor, etc.). If it judges compressor can be turned ON, it sends compressor ON sig-
nal 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.
SELF-DIAGNOSTIC SYSTEM
The self-diagnostic system is built into the front air control to quickly locate the cause of symptoms. Refer to
ATC-55, "
A/C System Self-diagnosis Function"
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AIR CONDITIONER CONTROL
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Description of Control SystemEJS003X7
The control system consists of input sensors, switches, the front air control (microcomputer) and outputs.
The relationship of these components is shown in the figure below:
Control OperationEJS003X8
Front air control
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AIR CONDITIONER CONTROL
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DISPLAY SCREEN
Displays the operational status of the system.
AUTO SWITCH

The compressor, intake door, air mix doors, outlet 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 oper-
ator.

When pressing AUTO switch, air inlet, air outlet, blower speed, and discharge air temperature are auto-
matically controlled.
TEMPERATURE CONTROL DIAL (TEMPERATURE CONTROL) (DRIVER SIDE)
Increases or decreases the set temperature.
TEMPERATURE CONTROL DIAL (TEMPERATURE CONTROL) (PASSENGER SIDE)
Increases or decreases the set temperature.
TEMPERATURE CONTROL DIAL (TEMPERATURE AND MODE CONTROL) (REAR)
Increases or decreases the set temperature. The mode also changes from foot at full hot setting, to foot/vent
mid-range (warm) setting, and then to panel on full cold setting.
RECIRCULATION () SWITCH

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

When REC switch is turned OFF, or when compressor is turned from ON to OFF, REC switch is automati-
cally turned OFF. 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.
DEFROSTER () SWITCH
Positions the air outlet doors to the defrost position. Also positions the intake doors to the outside air position.
REAR WINDOW DEFOGGER SWITCH
When switch is ON, rear window is defogged.
OFF SWITCH
The compressor and blower are OFF, the intake doors are set to the outside air position, and the air outlet
doors are set to the foot (75% foot and 25% defrost) position.
A/C SWITCH
The 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 (FRONT)
Controls the air discharge outlets.
FRONT BLOWER CONTROL DIAL
Manually control the blower speed. Seven speeds are available for manual control (as shown on the display
screen).

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AIR CONDITIONER CONTROL
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Rear Air Control
TEMPERATURE CONTROL DIAL (TEMPERATURE AND MODE CONTROL)
The temperature increases or decreases the set temperature. The mode also changes from foot at full hot set-
ting, to foot/vent at mid-range (warm) setting, and then to vent at full cold setting.
REAR BLOWER CONTROL DIAL
When the rear blower switch (front) is in the OFF position, the rear blower motor cannot operate.
When the rear blower switch (front) is in the REAR position, it allows the rear blower switch (rear) to control
the rear blower motor speed. In any other position (1-4), the rear blower switch (front) controls the rear blower
motor speed regardless of the rear blower switch (rear) position.
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AIR CONDITIONER CONTROL
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Discharge Air FlowEJS003X9
FRONT
REAR
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AIR CONDITIONER CONTROL
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System Description (Front)EJS003XA
SWITCHES AND THEIR CONTROL FUNCTION
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AIR CONDITIONER CONTROL
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System Description (Rear)EJS003XB
SWITCHES AND THEIR CONTROL FUNCTION
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AIR CONDITIONER CONTROL
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CAN Communication System DescriptionEJS003XC
Refer to LAN-5, "CAN COMMUNICATION" .

TROUBLE DIAGNOSIS
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DATA MONITOR
Operation Procedure
1. Touch “AIR CONDITIONER” on “SELECT TEST ITEM” screen.
2. Touch “DATA MONITOR” on “SELECT DIAG MODE” screen.
3. Touch either “ALL SIGNALS” or “SELECTION FROM MENU” on
“DATA MONITOR” screen.
4. When “SELECTION FROM MENU” is selected, touch items to
be monitored. When “ALL SIGNALS” is selected, all the items
will be monitored.
5. Touch “START”.
6. Touch “RECORD” while monitoring, then the status of the moni-
tored item can be recorded. To stop recording, touch “STOP”.
Display Item List
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All signals Monitors all the items.
Selection from menu Selects and monitors the individual item selected.
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Monitor item name “operation or
unit”Contents
IGN ON SW “ON/OFF” Displays “IGN Position (ON)/OFF, ACC Position (OFF)” status as judged from ignition switch signal.
COMP ON SIG “ON/OFF” Displays “COMP (ON)/COMP (OFF)” status as judged from air conditioner switch signal.
FAN ON SIG “ON/OFF” Displays “FAN (ON)/FAN (OFF)” status as judged from blower motor switch signal.