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LT-126
TRAILER TOW
Revision: November 20092006 QX56
TRAILER TOWPFP:93020
Component Parts and Harness Connector LocationEKS00BB1
System DescriptionEKS00BB2
Power is supplied at all times
to ignition relay, located in the IPDM E/R (intelligent power distribution module engine room), and
through 50A fusible link (letter f , located in the fuse and fusible link box)
to BCM (body control module) terminal 70, and
through 10A fuse (No. 32, located in the IPDM E/R)
1. Fuse and fusible link box2. IPDM E/R fuse layout 3. Fuse and relay box
4. IPDM E/R E118, E119, E120, E121, E122, E123, E124 5. A. Steering column
B. Data link connector M22
C. BCM M18, M19, M20
(View with instrument lower panel
LH removed) 6. A. Trailer turn relay LH E156
B. Battery
C. Trailer tow relay 2 E140
D. Trailer turn relay RH E157
7. A. Trailer tow relay 1 M51 B. Electric brake (pre-wiring) M76
(View with instrument lower panel
LH removed) 8. Trailer connector C2
9. Combination switch (lighting switch)
M28
WKIA4616E
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TRAILER TOWLT-127
C
DE
F
G H
I
J
L
M A
B
LT
Revision: November 2009 2006 QX56
through IPDM E/R terminal 61
to trailer tow relay 1 terminal 3, and
through 20A fuse (No. 53, located in the IPDM E/R)
to CPU (central processing unit) of the IPDM E/R, and
through 30A fusible link (letter j , located in the fuse and fusible link box)
to trailer tow relay 2 terminals 3 and 6, and
through 40A fusible link (letter k , located in the fuse and fusible link box)
to electric brake (pre-wiring) terminal 5.
With the ignition switch in the ON or START position, power is supplied
to ignition relay, located in the IPDM E/R, and
through 10A fuse (No. 59, located in the fuse and relay box)
to BCM terminal 38, and
through 10A fuse (No. 51, located in the IPDM E/R)
to trailer tow relay 2 terminal 1.
Ground is supplied
to BCM terminal 67
to electric brake (pre-wiring) terminal 1, and
through grounds M57, M61 and M79, and
to IPDM E/R terminals 38 and 59
to trailer tow relay 1 terminal 2
to trailer tow relay 2 terminal 2, and
to trailer connector terminal 2
to trailer turn relay LH and RH terminal 2
through grounds E9, E15 and E24.
TRAILER TAIL LAMP OPERATION
The trailer tail lamps are controlled by the trailer tow relay 1.
With the lighting switch in the parking and tail lamp ON (1ST) position, AUTO position (and the auto light sys-
tem is activated) or headlamp ON (2ND) position, power is supplied
through the tail lamp relay, located in the IPDM E/R
through 10A fuse (No. 36, located in the IPDM E/R)
through IPDM E/R terminal 49
to trailer tow relay 1 terminal 1.
When energized, trailer tow relay 1 supplies tail lamp power to trailer connector terminal 6.
TRAILER BRAKE, TURN SIGNAL AND HAZARD LAMP OPERATION
The trailer brake, turn signal and hazard lamps are controlled by the BCM through trailer turn relays (LH and
RH). When the brake pedal is depressed, the BCM receives stop lamp switch signal through CAN communi-
cation. If the brake pedal is depressed or either turn signal or the hazard lamps are turned on, the BCM sup-
plies voltage to the trailer turn relays (LH and RH) to make them cycle on and off.
Trailer turn relay LH output is supplied
through BCM terminal 52
to trailer turn relay LH terminal 1.
Trailer turn relay RH output is supplied
through BCM terminal 51
to trailer turn relay RH terminal 1.
Left trailer brake, turn signal and hazard lamp output is supplied
through trailer turn relay LH terminal 3
to trailer connector terminal 1.
Right trailer brake, turn signal and hazard lamp output is supplied
through trailer turn relay RH terminal 3
Page 2535 of 3383
LT-128
TRAILER TOW
Revision: November 20092006 QX56
to trailer connector terminal 4.
TRAILER BRAKE OPERATION
The trailer brake is controlled by the electric brake. The electric brake receives stop lamp switch signal at elec-
tric brake (pre-wiring) terminal 2 when the brake pedal is depressed.
When the brake pedal is depressed, power is supplied by the electric brake
through electric brake (pre-wiring) terminal 3
to trailer connector terminal 3.
TRAILER POWER SUPPLY OPERATION
The trailer power supply is controlled by the trailer tow relay 2.
When the ignition switch is in the ON or START position, power is supplied
through 10A fuse (No. 51, located in the IPDM E/R)
through IPDM E/R terminal 16
to trailer tow relay 2 terminal 1.
When energized, the trailer tow relay 2 supplies power
through trailer tow relay 2 terminals 5 and 7
to trailer connector terminal 5.
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LT-130
TRAILER TOW
Revision: November 20092006 QX56
Wiring Diagram — T/TOW —EKS00BB4
WKWA3665E
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LT-140
INTERIOR ROOM LAMP
Revision: November 20092006 QX56
Wiring Diagram — INT/L —EKS00BB8
WKWA2422E
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LT-148
INTERIOR ROOM LAMP
Revision: November 20092006 QX56
How to Proceed With Trouble DiagnosisEKS00BBA
1. Confirm the symptom or customer complaint.
2. Understand operation description and function description. Refer to LT- 1 3 5 , "
System Description" .
3. Carry out the Preliminary Check. Refer to LT- 1 4 8 , "
Preliminary Check" .
4. Check symptom and repair or replace the cause of malfunction.
5. Does the interior room lamp operate normally? If YES: GO TO 6. If NO: GO TO 4.
6. Inspection End.
Preliminary CheckEKS00BBB
INSPECTION FOR POWER SUPPLY AND GROUND CIRCUIT
1. CHECK FUSES OR FUSIBLE LINK
Check for blown BCM fuses or fusible link.
Refer to LT- 1 4 0 , "
Wiring Diagram — INT/L —" .
OK or NG
OK >> GO TO 2.
NG >> If fuse or fusible link is blown, be sure to eliminate cause of malfunction before installing new fuse or fusible link. Refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .
2. CHECK POWER SUPPLY CIRCUIT
1. Disconnect BCM connectors.
2. Check voltage between BCM connector and ground.
OK or NG
OK >> GO TO 3.
NG >> Check harness for open between BCM and fuse or fusible link.
3. CHECK GROUND CIRCUIT
Check continuity between BCM and ground.
OK or NG
OK >> Inspection End.
NG >> Check harness ground circuit.
Unit Power sourceFuse and fusible link No.
BCM Battery f
22
Ignition switch ON or START position 59
TerminalsIgnition switch position
(+) (– )O FF O N
Connector Terminal
M20 57
Ground Battery voltage Battery voltage
70 Battery voltage Battery voltage
M18 38 0V Battery voltage
WKIA1478E
Terminals
Continuity
Connector Terminal
M20 67Ground Yes
LIIA0915E
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LT-158
ILLUMINATION
Revision: November 20092006 QX56
to combination meter terminal 8
With the ignition switch in the ON or START position, power is supplied
to ignition relay, located in the IPDM E/R, and
through 10A fuse (No. 59, located in the fuse and relay box)
to BCM terminal 38, and
through 10A fuse [No. 14, located in the fuse block (J/B)]
to combination meter terminal 24.
Ground is supplied
to BCM terminal 67 and
to combination meter terminal 17
through grounds M57, M61 and M79, and
to IPDM E/R terminals 38 and 59
through grounds E9, E15 and E24.
ILLUMINATION OPERATION BY LIGHTING SWITCH
With the lighting switch in the 1ST or 2ND position (or if the auto light system is activated), the BCM receives
input signal requesting the illumination lamps to illuminate. This input signal is communicated to the IPDM E/R
across the CAN communication lines. The CPU of the IPDM E/R controls the tail lamp relay coil, which, when
energized, directs power
through 10A fuse (No. 36, located in the IPDM E/R)
through IPDM E/R terminal 49
to illumination control switch terminal 1
to power liftgate switch terminal 3
to front room/map lamp assembly (console box illumination) terminal 7
to hazard switch terminal 3
to rear sonar system OFF switch terminal 3
to glove box lamp terminal 1
to display control unit terminal 14
to 4WD shift switch terminal 7 (with 4-wheel drive)
to front air control terminal 23
to rear power vent window switch terminal 5
to DVD player terminal 12 (with DVD entertainment system)
to NAVI control unit terminal 61
to pedal adjusting switch terminal 5
to electric brake (pre-wiring) terminal 4 (with trailer tow)
to front and rear heated seat switch LH and RH terminal 5
to A/T device terminal 11
to VDC OFF switch terminal 3
to tow mode switch terminal 3
to headlamp aiming switch terminal 3
to clock terminal 3, and
through 10A fuse (No. 37, located in the IPDM E/R)
through IPDM E/R terminal 57
to AV switch terminal 3
to audio unit terminal 8
to rear air control terminal 1 and
to rear audio remote control unit terminal 6.
Illumination is controlled
through illumination control switch terminal 2
to power liftgate switch terminal 4
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ILLUMINATIONLT-159
C
DE
F
G H
I
J
L
M A
B
LT
Revision: November 2009 2006 QX56
to front room/map lamp assembly (console box illumination) terminal 8
to AV switch terminal 4
to hazard switch terminal 4
to audio unit terminal 7
to rear sonar system OFF switch terminal 4
to 4WD switch terminal 8 (with 4-wheel drive)
to front air control terminal 24
to rear power vent window switch terminal 6
to DVD player terminal 10 (with DVD entertainment system)
to pedal adjusting switch terminal 6
to A/T device terminal 12
to front heated seat switch LH and RH terminal 6
to VDC OFF switch terminal 4
to tow mode switch terminal 4
to headlamp aiming switch terminal 4
to clock terminal 4 and
to combination meter terminal 18.
Ground is supplied
to illumination control switch terminal 3
to glove box lamp terminal 2
to display control unit terminal 3
to rear heated seat switches terminal 6
to electric brake (pre-wiring) terminal 1 (with trailer tow) and
to compass and thermometer terminal 7
through grounds M57, M61 and M79, and
to NAVI control unit terminal 1
to rear air control terminal 3 and
to rear audio remote control unit terminal 15
through grounds B117 and B132.
With power and ground supplied, illumination lamps illuminate.
EXTERIOR LAMP BATTERY SAVER CONTROL
When the combination switch (lighting switch) is in the 1ST or 2ND position (or if auto light system is acti-
vated), and the ignition switch is turned from ON or ACC to OFF, the battery saver control function is activated.
Under this condition, the illumination lamps remain illuminated for 5 minutes, then the illumination lamps are
turned off.
When the lighting switch is turned from OFF to 1ST or 2ND position (or if auto light system is activated) after
illumination lamps are turned off by the battery saver control, the illumination lamps illuminate again.
Exterior lamp battery saver control mode can be changed by the function setting of CONSULT-II.
CAN Communication System DescriptionEKS00BBK
Refer to LAN-26, "CAN COMMUNICATION" .