INFINITI QX4 2005 Factory Service Manual

ATC-96
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
1. CHECK FUSES
Check 20A fuses [No. 24 and 27 (Located in the fuse and fusible link box)]. For fuse layout. Refer to PG-77,
"FUSE AND FUSIBLE LINK BOX" .
OK or NG
OK >> GO TO 2.
NG >> GO TO 10.
2. CHECK FRONT BLOWER MOTOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front blower motor connector.
3. Turn ignition switch ON.
4. Press the mode switch to select any mode except off.
5. Turn the front blower control dial to high.
6. Check voltage between front blower motor harness connector
M62 terminal 2 (W/L) and ground.
OK or NG
OK >> GO TO 12.
NG >> GO TO 3.
3. CHECK FRONT BLOWER MOTOR RELAY (SWITCH SIDE) POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front blower motor relay.
3. Turn ignition switch ON.
4. Check voltage between front blower motor relay harness con-
nector M107 terminals 5 (G/R) and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK FRONT BLOWER MOTOR RELAY
Turn ignition switch OFF.
Refer to ATC-100, "
Front Blower Motor Relay" .
OK or NG
OK >> GO TO 5.
NG >> Replace front blower motor relay.Fuses are good.
2 - Ground : Battery voltage.
WJIA1331E
5 - Ground : Battery voltage.
WJIA1359E

TROUBLE DIAGNOSIS
ATC-97
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
5. CHECK FRONT BLOWER MOTOR RELAY (SWITCH SIDE) CIRCUIT FOR OPEN
Check continuity between front blower motor relay harness connec-
tor M107 terminal 3 (W/L) and front blower motor harness connector
M62 terminal 2 (W/L).
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6. CHECK VARIABLE BLOWER CONTROL POWER SUPPLY CIRCUIT FOR OPEN
1. Disconnect variable blower control harness connector.
2. Check continuity between front blower motor relay harness con-
nector M107 terminals 3 (W/L) and variable blower control har-
ness connector M122 terminal 1 (W/L).
OK or NG
OK >> GO TO 7.
NG >> Repair harness or connector.
7. CHECK VARIABLE BLOWER CONTROL SIGNAL CIRCUIT
1. Disconnect front air control connector.
2. Check continuity between front air control harness connector
M49 terminal 13 (G/R) and variable blower control harness con-
nector M122 terminal 2 (G/R).
OK or NG
OK >> GO TO 8.
NG >> Repair harness or connector.
8. CHECK FRONT BLOWER MOTOR RELAY (COIL SIDE) POWER SUPPLY
1. Turn ignition switch ON.
2. Check voltage between front blower motor relay harness con-
nector M107 terminal 2 (Y/G) and ground.
OK or NG
OK >> GO TO 9.
NG >> Repair harness or connector.3 - 2 : Continuity should exist.
WJIA1360E
3 - 1 : Continuity should exist.
WJIA1361E
13 - 2 : Continuity should exist.
WJIA1362E
2 - Ground : Battery voltage.
WJIA1363E

ATC-98
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
9. CHECK FRONT BLOWER MOTOR RELAY (COIL SIDE) GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between front blower motor relay connector
M107 terminal 1 (R/B) and front air control harness connector
M49 terminal 26 (R/B).
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair harness or connector.
10. REPLACE FUSES
1. Replace fuses.
2. Activate the front blower motor.
3. Do fuses blow?
YES or NO
YES >> GO TO 11.
NO >> Inspection End.
11 . CHECK FRONT BLOWER MOTOR POWER SUPPLY CIRCUIT FOR SHORT
1. Turn ignition switch OFF.
2. Disconnect front blower motor connector and variable blower
control connector.
3. Check continuity between variable blower control harness con-
nector M122 terminal 1 (W/L) and ground.
OK or NG
OK >> GO TO 12.
NG >> Repair harness or connector.
12. CHECK VARIABLE BLOWER CONTROL SIGNAL CIRCUIT
1. Disconnect front air control connector.
2. Check continuity between front air control harness connector
M49 terminal 13 (G/R) and variable blower control harness con-
nector M122 terminal 2 (G/R).
OK or NG
OK >> GO TO 13.
NG >> Repair harness or connector.
13. CHECK FRONT BLOWER MOTOR
Refer to ATC-100, "
Front Blower Motor" .
OK or NG
OK >> GO TO 14.
NG >> Replace front blower motor.1 - 26 : Continuity should exist.
WJIA1364E
1 - Ground. : Continuity should not exist.
WJIA1365E
13 - 2 : Continuity should exist.
WJIA1366E

TROUBLE DIAGNOSIS
ATC-99
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
14. CHECK BLOWER MOTOR GROUND CIRCUIT
Check continuity between front blower motor harness connector
M62 terminal 1 (L/W) and variable blower control harness connector
M122 terminal 3 (L/W).
OK or NG
OK >> GO TO 15.
NG >> Repair harness or connector.
15. CHECK VARIABLE BLOWER CONTROL GROUND CIRCUIT
Check continuity between variable blower control harness connector
M122 terminal 4 (B/W) and ground.
OK or NG
OK >> Replace variable blower control. Refer to ATC-168,
"VARIABLE BLOWER CONTROL" .
NG >> Repair harness or connector.1 - 3 : Continuity should exist.
WJIA1367E
4 - ground : Continuity should exist.
WJIA1368E

ATC-100
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
COMPONENT INSPECTION
Front Blower Motor Relay
Check continuity between terminals by supplying 12 volts and
ground to coil side terminals of relay.
Front Blower Motor
Confirm smooth rotation of the blower motor.

Ensure that there are no foreign particles inside the blower unit.

Apply 12 volts to terminal + and ground to terminal - and verify
that the motor operates freely and quietly.
WJIA1401E
WJIA1265E

TROUBLE DIAGNOSIS
ATC-101
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
Rear Blower Motor CircuitEJS003XT
SYMPTOM:

Blower motor operation is malfunctioning.
INSPECTION FLOW
*1AT C - 6 0 , "Operational Check (Rear)"*2ATC-102, "Rear Blower Switch
(Rear) Circuit"
*3ATC-38, "SYMPTOM TABLE"
WJIA1266E

ATC-102
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
SYSTEM DESCRIPTION
Component Parts
Rear blower speed control system components are:

Front air control

Rear blower switch (front)

Rear air control

Rear blower motor resistor

Rear blower motor

Rear blower motor relay
System Operation
Rear Blower Control
When the rear blower control dial (front) is in the OFF position, the rear blower motor cannot operate.
When the rear blower control dial (front) is in the REAR position, it allows the rear blower switch (rear) to con-
trol 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.
DIAGNOSTIC PROCEDURE FOR REAR BLOWER MOTOR
Rear Blower Switch (Rear) Circuit
SYMPTOM:

Rear blower motor does not rotate when rear blower switch (front) is set to REAR position and the rear
blower switch (rear) is set at 1-4 speed.
1. CHECK REAR BLOWER MOTOR OPERATION
Blower motor rotates normally when rear blower control dial (front) is set at 1 - 4 speed.
OK or NG
OK >> GO TO 2.
NG >> Refer to ATC-104, "
Trouble Diagnosis Procedure For Rear Blower Motor (1 - 4 Speed)" .
2. CHECK REAR BLOWER SWITCH (FRONT)
Refer to ATC-110, "
Rear Blower Switch (Front)" .
OK or NG
OK >> GO TO 3.
NG >> Replace rear blower switch (front). Refer to ATC-147, "
FRONT AIR CONTROL" .
WJIA1280E

TROUBLE DIAGNOSIS
ATC-103
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
3. CHECK REAR AIR CONTROL
Refer to ATC-102, "
Rear Blower Switch (Rear) Circuit" .
OK or NG
OK >> GO TO 4.
NG >> Replace rear blower switch (rear). Refer to ATC-147, "
REAR AIR CONTROL" .
4. CHECK CIRCUIT CONTINUITY
1. Turn ignition switch OFF.
2. Disconnect rear blower switch (front) connector and rear air con-
trol connector.
3. Check continuity between rear blower switch (front) harness
connector M52 terminal 2 (BR) and rear blower switch (rear)
harness connector R208 terminal 10 (BR).
OK or NG
OK >> Inspection End.
NG >> Repair harness or connector.2 - 10 : Continuity should exist.WJIA1281E

ATC-104
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Trouble Diagnosis Procedure For Rear Blower Motor (1 - 4 Speed)
SYMPTOM:

Rear blower motor does not rotate when rear blower control dial (front) is set at 1 - 4 speed.
Inspection Flow
*1AT C - 6 0 , "Operational Check (Rear)"*2ATC-104, "Trouble Diagnosis Proce-
dure For Rear Blower Motor (1 - 4
Speed)"
*3AT C - 3 8 , "SYMPTOM TABLE"
WJIA1058E

TROUBLE DIAGNOSIS
ATC-105
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
1. DIAGNOSTIC PROCEDURE
Blower motor rotates normally at each speed.
OK or NG
OK >> Inspection End.
NG >> 1. Does not rotate at any speed, GO TO 2.
2. Does not rotate at 1 - 3 speed, GO TO 13.
3. Does not rotate at 4 speed, GO TO 18.
2. CHECK FUSES
Check 15A fuses [Nos. 10 and 11, located in the fuse block (J/B)]. Refer to PG-76, "
FUSE BLOCK-JUNCTION
BOX(J/B)" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 8.
3. CHECK REAR BLOWER MOTOR POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect rear blower motor connector.
3. Select any rear blower speed except OFF.
4. Turn ignition switch ON.
5. Check voltage between rear blower motor harness connector
B134 terminal 2 (L/R) and ground.
OK or NG
OK >> GO TO 11.
NG >> GO TO 4.
4. CHECK REAR BLOWER MOTOR RELAY
Turn ignition switch OFF.
Refer to AT C - 11 0 , "
Rear Blower Motor Relay" .
OK or NG
OK >> GO TO 5.
NG >> Replace rear blower motor relay.
5. CHECK REAR BLOWER MOTOR POWER FROM RELAY TO REAR BLOWER MOTOR
1. Reconnect rear blower motor connector.
2. Disconnect rear blower motor relay J-1.
3. Turn ignition switch ON.
4. Set rear blower switch (front) to any position except OFF, REAR,
or 4 - speed.
5. Momentarily (no more than 4 seconds), connect a jumper wire
between rear blower motor relay connector J-1 (harness side)
terminals 3 and 5.
OK or NG
OK >> GO TO 6.
NG >> GO TO 10.2 - Ground : Battery voltage.
WJIA0596E
Rear blower motor should rotate.WJIA2002E