2007 INFINITI QX56 ignition

ATC-68
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
1. Turn ignition switch ON.
2. Rotate temperature control dial (rear) to maximum heat.
3. Check voltage between front air control harness connector M50terminal 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-123, "Removal
and Installation" .
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 (rear) to maximum cold.
3. Check voltage between front air control harness connector M50 terminal 27 and terminal 28 while rotating temperature control
dial (rear) to maximum heat.
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-123, "
Removal and Installation".
4.CHECK AIR MIX DOOR MOTOR (REAR) 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 M50 terminal 27 and terminal 28.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.CHECK AIR MIX DOOR MOTOR (REAR) CIRCUITS FOR OPEN
ConnectorTe r m i n a l s
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
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control: M50 28 27
Rotate temp
control dial Battery
voltage
WJIA1746E
Continuity should exist.
WJIA1747E

TROUBLE DIAGNOSISATC-69
< SERVICE INFORMATION >
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1. Disconnect the air mix door motor (rear) harness connector.
2. Check continuity between front air control harness connector
M50 terminal 27, 28 and the air mix door motor (rear) harness
connector B155 terminal 1, 6.
OK or NG
OK >> Replace air mix door motor (rear). Refer to ATC-141,
"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.
7.CHECK PBR REFERENCE VOLTAGE CIRCUIT 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 2 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal
and Installation".
NG >> Repair or replace harness as necessary.
8.CHECK PBR REFERENCE VOLT AGE AND GROUND CIRCUITS
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector
M49 terminal 2 and terminal 15.
OK or NG
OK >> GO TO 10.
NG >> GO TO 9.
9.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR OPEN 27 - 1 : Continuity should exist.
28 - 6 : Continuity should exist.
LJIA0049E
Connector
Te r m i n a l s
Voltage (Ap-
prox.)
(+) (-)
Front air control: M49 2 15 5V
WJIA1729E
Continuity should not exist.
WJIA1730E
Continuity should exist.
WJIA1731E

ATC-70
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
1. Disconnect the air mix door motor (rear) harness connector.
2. Check continuity between air mix door motor (rear) harness con-nector B155 (B) terminal 3, 2 and front air control harness con-
nector M49 (A) terminal 2, 15.
OK or NG
OK >> Replace air mix door motor (rear). Refer to ATC-141,
"Removal and Installation".
NG >> Repair or replace harness as necessary.
10.CHECK PBR FEEDBACK VOLTAGE
1. Reconnect the front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M50 terminal 42 and ground while rotating temperature control dial
(rear) from maximum cold to maximum heat.
OK or NG
OK >> GO TO 12.
NG >> GO TO 11.
11 .CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 42 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal
and Installation" .
NG >> Repair or replace harness as necessary.
12.CHECK PBR FEEDBACK CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the air mix door motor (rear) harness connector and front air control harness connector.
3. Check continuity between air mix door motor (rear) harness con- nector B155 terminal 4 and front air control harness connector
M50 terminal 42.
OK or NG
OK >> Replace air mix door motor (rear). Refer to ATC-141,
"Removal and Installation".
NG >> Repair or replace harness as necessary.
Intake Door Motor CircuitINFOID:0000000003533254
SYMPTOM:• Intake door does not change.
• Intake door motor does not operate normally. 2 - 3 : Continuity should exist.
15 - 2 : Continuity should exist.
WJIA1748E
Voltage : Approx. 1V - 4.5V
LJIA0053E
Continuity should not exist.
WJIA1749E
Continuity should exist.
LJIA0054E

TROUBLE DIAGNOSISATC-73
< SERVICE INFORMATION >
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1. Turn ignition switch ON.
2. Check voltage between front air control harness connector M49 terminal 7 and terminal 8 while placing the HVAC system into
self-diagnostic mode.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.CHECK INTAKE 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 7, 8 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal
and Installation".
NG >> Repair or replace harness as necessary.
3.CHECK FRONT AIR CONTROL FOR GROUND AND POWER
1. Press the BACK button to back out of self-diagnostic mode.
2. Check voltage between front air control harness connector M49 terminal 7 and terminal 8 while placing the HVAC system into
self-diagnostic mode.
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-123, "
Removal and Installation" .
4.CHECK INTAKE 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 7 and terminal 8.
OK or NG
OK >> Replace intake door motor. Refer to ATC-139, "Removal
and Installation".
NG >> GO TO 5.
5.CHECK INTAKE DOOR MOTOR CIRCUITS FOR OPEN
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 7 8 Self-diagnostic
mode Battery volt-
age
WJIA1757E
7 - Ground : Continuity should not exist.
8 - Ground : Continuity should not exist.
WJIA1758E
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 8 7 Self-diagnostic
mode Battery
voltage
WJIA1759E
Continuity should exist.
WJIA1760E

TROUBLE DIAGNOSISATC-75
< SERVICE INFORMATION >
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• PBR (Built into defroster door motor)
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor
System Operation
The front air control determines defroster door position based on the position of the defroster switch. When the
defroster switch is depressed, the defroster door moto r rotates directing air to the defroster ducts. When any
mode other than defroster is selected, the defroster moto r rotates in the opposite direction closing off air flow
to the defroster ducts.
In the AUTO mode, the front air control determines defroster door position based on the ambient temperature,
the intake air temperature and the in-vehicle temperature.
COMPONENT DESCRIPTION
Defroster door motor
The defroster door motor is attached to the front heater & cooling
unit assembly. The front air control sends a voltage to rotate to the
defroster door directing the air flow either to the defroster ducts, or to
the floor ducts, depending on which way the voltage and ground are
applied to the motor leads. Motor rotation is conveyed to a lever
which activates the defroster door.
DIAGNOSTIC PROCEDURE FOR DEFROSTER DOOR MOTOR
1.CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Press the defroster switch ( ).
3. Check voltage between front air control harness connector M49 terminal 20 and terminal 19 and press the defroster switch ( )
again.
WJIA1354E
WJIA0592E
WJIA2277E

ATC-76
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.CHECK DEFROSTER 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 19, 20 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal
and Installation".
NG >> Repair or replace harness as necessary.
3.CHECK FRONT AIR CONTROL FOR GROUND AND POWER
1. Press the defroster switch ( ).
2. Check voltage between front air control harness connector M49 terminal 19 and terminal 20 and pr ess the defroster switch ( )
again.
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-123, "
Removal and Installation".
4.CHECK DEFROSTER 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 19 and terminal 20.
OK or NG6
OK >> GO TO 6.
NG >> GO TO 5.
5.CHECK DEFROSTER DOOR MOTOR CIRCUITS FOR OPEN
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 20 19 Press de-
froster
switch Battery
voltage
19 - Ground : Continuity should not exist.
20 - Ground : Continuity should not exist.
WJIA1766E
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 19 20 Press de-
froster
switch Battery
voltage
WJIA1767E
Continuity should exist.
WJIA1773E

TROUBLE DIAGNOSISATC-77
< SERVICE INFORMATION >
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1. Disconnect the defroster door motor harness connector.
2. Check continuity between front air control harness connector
M49 terminal 19, 20 and the defroster door motor harness con-
nector M144 terminal 1, 6.
OK or NG
OK >> Replace defroster door motor. Refer to ATC-138,
"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.
7.CHECK PBR REFERENCE VOLTAGE CIRCUIT 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 2 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal
and Installation".
NG >> Repair or replace harness as necessary.
8.CHECK PBR REFERENCE VOLT AGE AND GROUND CIRCUITS
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector
M49 terminal 2 and terminal 15.
OK or NG
OK >> GO TO 10.
NG >> GO TO 9.
9.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR OPEN 19 - 1 : Continuity should exist.
20 - 6 : Continuity should exist.
WJIA0553E
Connector
Te r m i n a l s
Voltage (Ap-
prox.)
(+) (-)
Front air control: M49 2 15 5V
WJIA1729E
Continuity should not exist.
WJIA1730E
Continuity should exist.
WJIA1731E

ATC-78
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
1. Disconnect the defroster door motor harness connector.
2. Check continuity between defroster door motor harness connec-tor M144 (B) terminal 3, 2 and fr ont air control harness connec-
tor M49 (A) terminal 2, 15.
OK or NG
OK >> Replace defroster door motor. Refer to ATC-138,
"Removal and Installation".
NG >> Repair or replace harness as necessary.
10.CHECK PBR FEEDBACK VOLTAGE
1. Reconnect the front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49 terminal 25 and ground while cycling defroster switch on and off.
OK or NG
OK >> GO TO 12.
NG >> GO TO 11.
11 .CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 25 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal
and Installation" .
NG >> Repair or replace harness as necessary.
12.CHECK PBR FEEDBACK CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the defroster door motor harness connector and front air control harness connector.
3. Check continuity between defroster door motor harness connec- tor M144 terminal 4 and front air control harness connector M49
terminal 25
OK or NG
OK >> Replace defroster door motor. Refer to ATC-138,
"Removal and Installation".
NG >> Repair or replace harness as necessary.
Front Blower Motor CircuitINFOID:0000000003533256
SYMPTOM:• Blower motor operation is malfunctioning.
INSPECTION FLOW
2 - 3 : Continuity should exist.
15 - 2 : Continuity should exist.
WJIA1777E
Voltage : Approx. 1V - 4.5V
WJIA1786E
Continuity should not exist.
WJIA1787E
Continuity should exist.
WJIA0558E