relay INFINITI QX56 2004 Factory Owner's Manual

AIR CONDITIONER CONTROL
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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"
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ATC-86
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Revision: August 20072004 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 M62.
3. Turn ignition switch ON.
4. Press the MODE switch to select any mode except OFF.
5. Set front fan switch 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 M107.
3. Check voltage between front blower motor relay harness con-
nector M107 terminals 5 (GR) and 7 (P), and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK FRONT BLOWER MOTOR RELAY
Refer to ATC-89, "
Front Blower Motor Relay" .
OK or NG
OK >> GO TO 5.
NG >> Replace front blower motor relay.
5. CHECK FRONT BLOWER MOTOR RELAY (SWITCH SIDE) CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect blower motor relay connector M107 and front blower
motor connector M62.
3. Check continuity between front blower motor relay harness con-
nector M107 terminals 3 (W/L) and 6 (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.2 - Ground : Battery voltage should exist.
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5, 7 - Ground : Battery voltage should exist.
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3, 6 - 2 : Continuity should exist.
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TROUBLE DIAGNOSIS
ATC-87
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6. CHECK VARIABLE BLOWER CONTROL POWER SUPPLY CIRCUIT FOR OPEN
1. Disconnect variable blower control connector M122.
2. Check continuity between front blower motor relay harness con-
nector M107 terminals 3 (W/L) and 6 (W/L), and variable blower
control harness 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 M49.
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 1 (Y/G) and ground.
OK or NG
OK >> GO TO 9.
NG >> Repair harness or connector.
9. CHECK FRONT BLOWER MOTOR RELAY (COIL SIDE) GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between front blower motor relay harness con-
nector M107 terminal 2 (R/B) and front air control harness con-
nector M49 terminal 26 (R/B).
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> Repair harness or connector.3, 6 - 1 : Continuity should exist.
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13 - 2 : Continuity should exist.
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1 - Ground : Battery voltage should exist.
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2 - 26 : Continuity should exist.
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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 2 and ground to terminal 1 and verify
that the motor operates freely and quietly.
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SYSTEM DESCRIPTION
Component Parts
Rear blower speed control system components are:

Front air control

Rear fan switch (front)

Rear fan switch (rear)

Rear blower motor resistor

Rear blower motor

Rear blower motor relay
System Operation
NOTE:
The rear heat or A/C cannot operate unless the front heat or A/C is on.
Rear Blower Control
When the rear fan switch (front) is in the off (O) position, the rear blower motor cannot operate.
When the rear fan switch (front) is in the rear (R) position, it allows the rear fan switch (rear) to control the rear
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.
DIAGNOSTIC PROCEDURE FOR REAR BLOWER MOTOR
Rear Fan Switch (Rear) Circuit
SYMPTOM:

Rear blower motor does not rotate when rear fan switch (front) is set to rear (R) position.
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ATC-94
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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 B134.
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
Refer to ATC-99, "
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. Turn ignition switch OFF.
2. Reconnect rear blower motor connector.
3. Disconnect rear blower motor relay J1.
4. Turn ignition switch ON.
5. Set rear fan switch (front) to any position except off (0), rear (R),
or 4 - speed.
6. Momentarily (no more than 4 seconds), connect a jumper wire
between rear blower motor relay connector J1 terminals 3 and 5.
OK or NG
OK >> GO TO 6.
NG >> GO TO 10.1 - Ground : Battery voltage should exist.
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Rear blower motor should rotate.LJIA0100E

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6. CHECK REAR BLOWER MOTOR RELAY (COIL SIDE) POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect fuse block (J/B) connector M39.
3. Turn ignition switch ON.
4. Set rear fan switch (front) to any position except off (0), rear (R),
or 4 - speed.
5. Check voltage between fuse block (J/B) harness connector M39
terminal 3Q (W/L) and ground.
OK or NG
OK >> GO TO 7.
NG >> GO TO 20.
7. CHECK REAR BLOWER MOTOR RELAY (COIL SIDE) GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect fuse block (J/B) connector M3.
3. Check continuity between fuse block (J/B) harness connector
M3 terminal 7N (B) and ground.
OK or NG
OK >> Replace fuse block (J/B).
NG >> Repair harness or connector.
8. REPLACE FUSE
Refer to PG-76, "
FUSE BLOCK-JUNCTION BOX(J/B)" .
Fuse should not open when rear blower motor is activated.
OK or NG
OK >> Inspection End.
NG >> GO TO 9.
9. CHECK REAR BLOWER MOTOR POWER SUPPLY CIRCUIT FOR SHORT
1. Turn ignition switch OFF.
2. Disconnect battery cables and rear blower motor connector
B134.
3. Check continuity between rear blower motor harness connector
B134 terminal 2 (L/R) and ground.
OK or NG
OK >> Check rear blower motor. Refer to ATC-100, "Rear
Blower Motor" .
NG >> Repair harness or connector.1 - Ground : Battery voltage should exist.
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7N - Ground : Continuity should exist.
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2 - Ground : Continuity should not exist.
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ATC-96
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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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ATC-98
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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
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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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