INFINITI QX56 2004 Factory Service Manual

ATC-96
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
10. CHECK REAR BLOWER MOTOR RELAY (SWITCH SIDE) POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect fuse block (J/B) connector M3 and rear blower motor
connector B134.
3. Check continuity between fuse block (J/B) harness connector
M3 terminal 3N (SB) and 8N (L/R) and rear blower motor har-
ness connector B134 terminal 2 (L/R).
OK or NG
OK >> GO TO 20.
NG >> Repair harness or connector.
11 . CHECK REAR BLOWER MOTOR
Refer to ATC-100, "
Rear Blower Motor" .
OK or NG
OK >> GO TO 12.
NG >> Replace rear blower motor. Refer to ATC-141, "
REAR BLOWER MOTOR" .
12. CHECK REAR FAN SWITCH (FRONT)
Refer to ATC-99, "
Rear Fan Switch (Front)" .
OK or NG
OK >> GO TO 15.
NG >> Replace rear fan switch (front). Refer to ATC-135, "
FRONT AIR CONTROL" .
13. CHECK REAR BLOWER MOTOR RESISTOR
Refer to ATC-100, "
Rear Blower Motor Resistor" .
OK or NG
OK >> GO TO 14.
NG >> Replace rear blower motor resistor. Refer to ATC-156, "
Removal and Installation" .
14. CHECK REAR FAN SWITCH (FRONT) CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect rear fan switch (front) M52.
3. Reconnect rear blower motor resistor harness connector B133.
4. Turn ignition switch ON.
5. Check voltage between each rear fan switch (front) connector
M52 terminals 3 (LG), 7 (W/L), and 8 (G), and ground.
OK or NG
OK >> GO TO 17.
NG >> GO TO 16.3N, 8N - 2 : Continuity should exist.
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Te r m i n a l N o .
Voltage
(Approx.)
(+) (-)
3
Ground 12V 7
8
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TROUBLE DIAGNOSIS
ATC-97
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Revision: August 20072004 QX56
15. CHECK REAR BLOWER MOTOR GROUND CIRCUIT TO REAR BLOWER MOTOR RESISTOR
1. Turn ignition switch OFF.
2. Disconnect rear blower motor connector B134 and rear blower
motor resistor connector B133.
3. Check continuity between rear blower motor connector B134
terminal 1 (L/B) and rear blower motor resistor harness connec-
tor B133 terminal 3 (L/B).
4. Check continuity between rear blower motor connector B134
terminal 1 (L/B) and ground.
OK or NG
OK >> GO TO 16.
NG >> Repair harness or connector.
16. CHECK REAR FAN SWITCH (FRONT) CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect rear fan switch (front) connector M52.
3. Check continuity between rear fan switch (front) connector M52
terminals 3 (LG), 7 (W/L), and 8 (G), and rear blower motor
resistor connector B133 terminals 1 (LG), 4 (W/L), and 2 (G).
OK or NG
OK >> Inspection End.
NG >> Repair harness or connector.
17. CHECK REAR FAN SWITCH (FRONT) CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect rear fan switch (rear) (Rear air control) connector
R208.
3. Check continuity between rear fan switch (front) connector M52
terminals 3 (LG), 5 (L/B), 7 (W/L), and 8 (G), and rear fan switch
(rear) (Rear air control) connector R208 terminals 9 (LG), 6 (L/
B), 8 (W/L), and 7 (G).
OK or NG
OK >> GO TO 18.
NG >> Repair harness or connector.1 - 3 : Continuity should exist.
1 - Ground : Continuity should not exist.
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Te r m i n a l N o .
Continuity
Rear fan switch (front) Rear blower motor resistor
31
Should exist 74
82
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Terminal No.
Continuity
Rear fan switch (front) Rear fan switch (rear)
39
Should exist 56
78
87
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ATC-98
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
18. CHECK REAR FAN SWITCH (FRONT)
Refer to ATC-99, "
Rear Fan Switch (Front)" .
OK or NG
OK >> GO TO 19.
NG >> Replace rear fan switch (front). Refer to ATC-135, "
FRONT AIR CONTROL" .
19. CHECK REAR FAN SWITCH (REAR)
Refer to ATC-99, "
Rear Fan Switch (Rear)" .
OK or NG
OK >> Inspection End.
NG >> Replace rear fan switch (rear). Refer to ATC-135, "
REAR AIR CONTROL" .
20. CHECK CIRCUIT BETWEEN FRONT AIR CONTROL AND FUSE BLOCK (J/B) [REAR BLOWER
MOTOR RELAY (COIL SIDE) POWER]
1. Disconnect front air control connector M50 and fuse block (J/B)
connector M39.
2. Check continuity between front air control harness connector
M50 terminal 38 (W/L) and fuse block (J/B) connector M39 ter-
minal 3Q (W/L).
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL"
NG >> Repair harness or connector.38 - 3Q : Continuity should exist.LJ IA 0 111E

TROUBLE DIAGNOSIS
ATC-99
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Revision: August 20072004 QX56
COMPONENT INSPECTION
Rear Blower Motor Relay
Check circuit continuity between terminals by supplying 12 volts and
ground to coil side terminals of relays.
Rear Fan Switch (Rear)
Check continuity between terminals at each switch position.
Rear Fan Switch (Front)
Check continuity between terminals at each switch position.
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ATC-100
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Rear Blower Motor
Check that there are no foreign particles inside the intake unit.
Apply 12 volts to terminal 2 and ground to terminal 1 and ensure that
the blower motor rotates freely and quietly.
Rear Blower Motor Resistor
Check continuity between terminals. There will be resistance, but
there should not be an open or short between any two terminals.
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TROUBLE DIAGNOSIS
ATC-101
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Revision: August 20072004 QX56
Rear Air Control CircuitEJS002CK
SYMPTOM:

Temperature cannot be adjusted from the rear air control.
INSPECTION FLOW
*1ATC-59, "Operational Check (Rear)"*2AT C - 5 3 , "A/C System Self-diagno-
sis Function"
*3AT C - 5 5 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-102, "DIAGNOSTIC PROCE-
DURE FOR REAR AIR CONTROL"
*5AT C - 7 3 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (REAR)"
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ATC-102
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
SYSTEM DESCRIPTION
Component Parts
Rear air control system components are:

Front air control

Rear air control

Air mix door motor (rear)

Rear blower motor relay

Rear blower motor resistor

Rear blower motor
System Operation
Rear Air Control
When the rear fan switch (front) (integral to the front air control) is in the rear (R) position the rear blower motor
speeds and the rear temperature/mode are controlled by the rear fan switch (rear) and the rear temperature/
mode dial (rear) (both integral to the rear air control).
DIAGNOSTIC PROCEDURE FOR REAR AIR CONTROL
SYMPTOM:

Blower motor operation is malfunctioning. Refer to ATC-90, "Rear Blower Motor Circuit" .

Temperature/mode operation is malfunctioning.
1. CHECK OPERATION FROM FRONT AIR CONTROL
Does rear temperature/mode operate normally from front air control?
YES or NO
YES >> GO TO 2.
NO >> Refer to AT C - 7 3 , "
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (REAR)" .
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TROUBLE DIAGNOSIS
ATC-103
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Revision: August 20072004 QX56
2. CHECK CIRCUIT BETWEEN REAR AIR CONTROL AND FRONT AIR CONTROL FOR OPEN AND
SHORT
1. Turn ignition switch OFF.
2. Disconnect front air control M50 and rear temperature/mode dial
(rear) (Rear air control) connector R209.
3. Check continuity between front air control harness connector
M50 terminal 33 (V) and rear temperature/mode dial (rear)
(Rear air control) connector R209 terminal 5 (V).
4. Check continuity between rear temperature/mode dial (rear)
(Rear air control) connector R209 terminal 5 (V) and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK CIRCUIT BETWEEN REAR AIR CONTROL AND AIR MIX DOOR MOTOR (REAR) FOR OPEN
OR SHORT
1. Disconnect air mix door motor (rear) connector B155.
2. Check continuity between rear temperature/mode dial (rear)
(Rear air control) connector R209 terminal 2 (P) and 4 (Y) and
air mix door motor (rear) harness connector B155 terminal 2 (P)
and 3 (Y).
3. Check continuity between rear temperature/mode dial (rear)
(Rear air control) connector R209 terminals 2 (P) and 4 (Y) and
ground.
OK or NG
OK >> Replace rear air control [rear temperature/mode dial (rear)]. Refer to ATC-135, "REAR AIR CON-
TROL" .
NG >> Repair harness or connector.33 - 5 Continuity should exist.
5 - Ground Continuity should not exist.
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2 - 2 Continuity should exist.
4 - 3 Continuity should exist.
2, 4 - Ground Continuity should not exist.
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ATC-104
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Magnet Clutch CircuitEJS002CL
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1AT C - 5 6 , "Operational Check (Front)"*2ATC-53, "A/C System Self-diagnosis
Function"
*3AT C - 5 5 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-125, "Ambient Sensor Circuit"*5ATC-133, "Intake Sensor Circuit"*6AT C - 3 5 , "SYMPTOM TABLE"
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TROUBLE DIAGNOSIS
ATC-105
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Revision: August 20072004 QX56
SYSTEM DESCRIPTION
The front air control controls compressor operation based on ambient and intake temperature and a signal
from ECM.
Low Temperature Protection Control
The front air control will turn the compressor ON or OFF as determined by a signal detected by the intake sen-
sor and the ambient sensor.
When intake air temperature is higher than the preset value, the compressor turns ON. The compressor turns
OFF when intake air temperature is lower than the preset value. That preset value is dependent on the ambi-
ent temperature, refer to the following table.
DIAGNOSTIC PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
1. CHECK INTAKE AND AMBIENT SENSOR CIRCUITS
Check intake and ambient sensors. Refer to ATC-53, "
A/C System Self-diagnosis Function" .
OK or NG
OK >> GO TO 2.
NG >>

Malfunctioning intake sensor. Refer to ATC-133, "Intake Sensor Circuit" .

Malfunctioning ambient sensor. Refer to ATC-125, "Ambient Sensor Circuit" .
Ambient temperature °C (°F)Co mp re s so r ON
intake temperature °C (°F)C o m p r e s s o r O F F
intake temperature °C (°F)
0 (32) 5.5 (41.9) 5.0 (41.0)
10 (50) 4.5 (40.1) 4.0 (39.2)
20 (68) 2.5 (36.5) 2.0 (35.6)
30 (86) 2.0 (35.6) 1.0 (33.8)
40 (104) 2.0 (35.6) 0.5 (32.9)
50 (122) 2.0 (35.6) 0.5 (32.9)
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