2006 INFINITI QX56 air condition

ATC-60
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Operational Check (Rear)EJS003XM
The purpose of the operational check is to confirm that the system operates properly.
CHECKING BLOWER
1. Turn the rear blower control dial to switch position "1". Blower should operate on low speed.
2. Turn the rear blower control dial counterclockwise to switch position "2", "3", and "4" until all speeds are
checked.
3. Leave blower on MAX speed.
If NG, go to trouble diagnosis procedure for ATC-101, "
Rear Blower Motor Circuit" .
If OK, continue the check.
CHECKING TEMPERATURE DECREASE
1. Rotate temperature and mode dial fully counterclockwise.
2. Check for cold air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operation if OK, go to trouble diagnosis procedure for ATC-121,
"Insufficient Cooling" . If air mix door motor appears to be malfunctioning, go to AT C - 7 9 , "DIAGNOSTIC PRO-
CEDURE FOR AIR MIX DOOR MOTOR (REAR)" .
If OK, continue the check.
CHECKING TEMPERATURE INCREASE
1. Rotate temperature and mode dial clockwise.
2. Check for hot air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operation. If OK, go to trouble diagnosis procedure for ATC-128,
"Insufficient Heating" . If air mix door motor appears to be malfunctioning, go to AT C - 7 9 , "DIAGNOSTIC PRO-
CEDURE FOR AIR MIX DOOR MOTOR (REAR)" .
If OK, continue the check. Conditions : Engine running and at normal operating temperature

ATC-62
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
COMPONENT DESCRIPTION
Front Air Control
The front air control has a built-in microcomputer which processes
information sent from various sensors needed for air conditioner
operation. The air mix door motors, mode door motor, intake door
motor, defroster door motor, blower motor and compressor are then
controlled.
The front air control is unitized with control mechanisms. When the
various switches and temperature dials are operated, data is input to
the front air control.
Self-diagnostic functions are also built into the front air control to pro-
vide quick check of malfunctions in the auto air conditioner system.
Potentio Temperature Control (PTC)
There are two PTCs (passenger and driver) built into the front air
control. They can be set at an interval of 0.5°C (1.0 °F) in the 16 °C
(60 °F) to 32 °C (90 °F) temperature range by rotating the temperature
dial. The set temperature is displayed.
DIAGNOSTIC PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
WJIA0544E
WJIA1050E
WJIA0414E

ATC-66
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
COMPONENT DESCRIPTION
Mode Door Motor
The mode door motor is attached to the heater & cooling unit. It
rotates so that air is discharged from the outlet as indicated by the
front air control. Motor rotation is conveyed to a link which activates
the mode door.
DIAGNOSTIC PROCEDURE FOR MODE DOOR MOTOR
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Press the mode switch to the B/L ( ) mode.
3. Check voltage between front air control harness connector M49 terminal 5 and terminal 6 while pressing the mode switch to the
floor ( ) mode.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK MODE DOOR MOTOR CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 5, 6 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
WJIA0587E
Connector Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 6 5 Press
mode
switch Battery
voltage
WJIA1727E
5 - Ground : Continuity should not exist.
6 - Ground : Continuity should not exist.
WJIA1734E

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Revision: November 2009 2006 QX56
3. CHECK FRONT AIR CONTROL FOR GROUND AND POWER
1. Press the mode switch to the D/F ( ) mode.
2. Check voltage between front air control harness connector M49 terminal 5 and terminal 6 while pressing the mode switch to the
vent ( ) mode.
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-144, "
FRONT AIR CONTROL" .
4. CHECK MODE DOOR MOTOR AND CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 5 and terminal 6.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. CHECK MODE DOOR MOTOR CIRCUITS FOR OPEN
1. Disconnect the mode door motor harness connector.
2. Check continuity between front air control harness connector M49 terminal 5, 6 and the mode door motor harness connector
terminal 5, 6.
OK or NG
OK >> Replace mode door motor. Refer to ATC-161, "Removal
and Installation" .
NG >> Repair or replace harness as necessary.
6. CHECK FRONT AIR CONTROL FOR PBR POWER AND GROUND
1. Reconnect front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49 terminal 2 and terminal 15.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
Connector Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 5 6 Press
mode
switch Battery
voltage
WJIA1742E
Continuity should exist.
WJIA1728E
5 - 5 : Continuity should exist.
6 - 6 : Continuity should exist.
LJIA0027E
Connector Te r m i n a l s
Voltage
(Approx.)
(+) (-)
Front air control: M49 2 15 5V
WJIA1729E

ATC-72
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
COMPONENT DESCRIPTION
Air Mix Door Motors
The driver (1) and front passenger (2) air mix door motors are
attached to the front heater & cooling unit assembly. The rear air mix
door motor is attached to the rear heater & cooling unit. These
motors rotate so that the air mix door is opened or closed to a posi-
tion set by the front (or rear) air control. Motor rotation is then con-
veyed through a shaft and the air mix door position is then fed back
to the front air control by the PBR built into the air mix door motors.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (DRIVER)
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32° C (90°F).
3. Check voltage between front air control harness connector M49 terminal 3 and terminal 4 while rotating temperature control dial
(driver) to 16 °C (60 °F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 3, 4 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
WJIA2309E
WJIA1245E
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 3 4 Rotate temp
control dial Battery
voltage
WJIA1735E
3 - Ground : Continuity should not exist.
4 - Ground : Continuity should not exist.
WJIA1736E

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Revision: November 2009 2006 QX56
3. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32 °C (90 °F).
3. Check voltage between front air control harness connector M49 terminal 3 and terminal 4 while rotating temperature control dial
(driver) to 16 °C (60 °F).
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-144, "
FRONT AIR CONTROL" .
4. CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 3 and terminal 4.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR OPEN
1. Disconnect the air mix door motor (driver) harness connector.
2. Check continuity between front air control harness connector M49 terminal 3, 4 and the air mix door motor (driver) harness
connector M147 terminal 1, 6.
OK or NG
OK >> Replace air mix door motor (driver). Refer to ATC-163,
"FRONT AIR MIX DOOR MOTOR (PASSENGER)" .
NG >> Repair or replace harness as necessary.
Connector Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 4 3
Rotate temp
control dial Battery
voltage
WJIA1737E
Continuity should exist.
WJIA1738E
3 - 1 : Continuity should exist.
4 - 6 : Continuity should exist.
WJIA0588E

ATC-76
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (PASSENGER)
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (passenger) to 32 °C (90 °F).
3. Check voltage between front air control harness connector M50 terminal 36 and terminal 37 while rotating temperature control
dial (passenger) to 16 °C (60 °F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK AIR MIX DOOR MOTOR (PASSENGER) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 36, 37 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
3. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (passenger) to 16 °C (60 °F).
3. Check voltage between front air control harness connector M50 terminal 36 and terminal 37 while rotating temperature control
dial (passenger) to 32 °C (90 °F).
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-144, "
FRONT AIR CONTROL" .
Connector Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M50 37 36 Rotate temp
control dial Battery
voltage
WJIA1740E
36 - Ground : Continuity should not exist.
37 - Ground : Continuity should not exist.
WJIA1741E
Connector Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M50 36 37 Rotate temp
control dial Battery
voltage
WJIA1778E

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Revision: November 2009 2006 QX56
12. CHECK PBR FEEDBACK CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the air mix door motor (passenger) harness connec- tor and front air control harness connector.
3. Check continuity between air mix door motor (passenger) har- ness connector M143 terminal 4 and front air control harness
connector M50 terminal 41.
OK or NG
OK >> Replace air mix door motor (passenger). Refer to AT C -
162, "FRONT AIR MIX DOOR MOTOR (DRIVER)" .
NG >> Repair or replace harness as necessary.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (REAR)
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (rear) to maximum heat.
3. Check voltage between front air control harness connector M50 terminal 27 and terminal 28 while rotating temperature control
dial (rear) to maximum cold.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK AIR MIX DOOR MOTOR (REAR) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 27, 28 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary. Continuity should exist.
WJIA0550E
Connector
Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M50 27 28
Rotate temp
control dial Battery
voltage
WJIA1744E
27 - Ground : Continuity should not exist.
28 - Ground : Continuity should not exist.
WJIA1745E