2004 INFINITI QX56 air condition

AIR CONDITIONER CONTROL
ATC-25
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
MAGNET CLUTCH CONTROL
When the A/C or DEF switch is activated, the front air control outputs a compressor ON signal to the BCM.
Upon receiving this input, the BCM sends a compressor ON signal to the ECM via CAN communication lines.
The ECM then judges whether the compressor can be turned ON, based on each sensor status (refrigerant
pressure sensor signal, throttle angle sensor, etc.). If it determines the compressor can be turned ON, a com-
pressor ON signal is sent to the IPDM E/R via CAN communication lines.
Upon receipt of a compressor ON signal, the IPDM E/R turns ON the A/C relay which engages the magnet
clutch and operates the A/C compressor.
SELF-DIAGNOSTIC SYSTEM
A self-diagnostic system is built into the front air control to quickly locate the cause of symptoms. Refer to
ATC-53, "
A/C System Self-diagnosis Function"
WJIA0751E

ATC-26
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
Description of Control SystemEJS002BY
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 OperationEJS002BZ
Front air control
WJIA0755E
WJIA0756E

AIR CONDITIONER CONTROL
ATC-27
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
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.
TEMPERATURE DIAL (DRIVER)
Increases or decreases the driver zone temperature.
TEMPERATURE DIAL (PASSENGER)
Increases or decreases the passenger zone temperature.
RECIRCULATION SWITCH ()

When pressed an indicator turns ON in the display, and air inlet is set to recirculation mode.

Recirculation mode is cancelled by pressing the switch again, turning ON the front defroster, pressing the
OFF switch, or pressing the A/C switch to turn off the A/C system and compressor.
DEFROSTER () SWITCH
Positions the air outlet doors to the defrost position. Also positions the intake door to the outside air position.
REAR WINDOW DEFOGGER SWITCH
When switch is ON, rear window is defogged.
OFF SWITCH (HOLD FAN DOWN SWITCH UNTIL SYSTEM SHUTS OFF)
The compressor and blower are OFF, the intake door is 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
Controls the air discharge outlets.
FRONT FAN SWITCH
Manually controls the blower speed. Seven speeds are available for manual control (as shown on the display
screen).
REAR FAN SWITCH (FRONT)
Manually controls the rear blower speed. Four speeds are available for manual control. When the rear fan
switch (front) is in the off (0) position, the rear blower motor cannot operate. Position (R) allows control of rear
blower speed and rear temperature/mode operation to be transferred to rear air control.
REAR TEMPERATURE/MODE DIAL (FRONT)
Increases or decreases the rear zone temperature and adjusts the mode simultaneously. FLOOR is full hot
setting, FLOOR/PANEL is warm setting, and PANEL is full cold setting.

ATC-28
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
Rear Air Control
REAR TEMPERATURE/MODE DIAL (REAR)
Increases or decreases the rear zone temperature and adjusts the mode simultaneously. FLOOR is full hot
setting, FLOOR/PANEL is warm setting, and PANEL is full cold setting. Operates only with rear fan switch
(front) is in the (R) position.
REAR FAN CONTROL SWITCH (REAR)
When the rear fan switch (front) is in the (R) position, it allows the rear fan switch (rear) to control the blower
motor speed. In any other position (1-4), the rear fan switch (front) controls the rear blower motor speed
regardless of the rear fan switch (rear) position.
LJIA0024E

AIR CONDITIONER CONTROL
ATC-29
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
Discharge Air FlowEJS002C0
FRONT
REAR
WJIA0540E
WJIA0528E
WJIA0541E
WJIA0893E

ATC-30
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
System Description (Front)EJS002C1
CONTROLS AND THEIR FUNCTIONS
WJIA1680E
WJIA0757E

AIR CONDITIONER CONTROL
ATC-31
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
System Description (Rear)EJS002C2
CONTROLS AND THEIR FUNCTIONS
WJIA0623E
WJIA0758E

ATC-32
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
CAN Communication System DescriptionEJS002C3
Refer to LAN-5, "CAN COMMUNICATION" .