2008 INFINITI QX56 relay

HEADLAMPEXL-7
< FUNCTION DIAGNOSIS >
C
DE
F
G H
I
J
K
M A
B
EXL
N
O P
FUNCTION DIAGNOSIS
HEADLAMP
System DiagramINFOID:0000000001547094
System DescriptionINFOID:0000000001547095
Control of the headlamp system operation is dependent upon the position of the lighting switch (combination
switch). When the lighting switch is placed in the 2nd position, the BCM (body control module) receives input
requesting the headlamps and park lamps to illuminate. Th is input is communicated to the IPDM E/R (intelli-
gent power distribution module engine room) via the CA N communication lines. The CPU (central processing
unit) of the IPDM E/R controls the headlamp high and headl amp low relay coils. When energized, these relays
direct power to the respective headlamps, which then illuminate.
Component Parts LocationINFOID:0000000001547096
Component DescriptionINFOID:0000000001547097
XENON HEADLAMP
A Xenon type headlamp is adapted to the low beam headlamps. Xenon bulbs do not use a filament.
Instead,they produce light when a high voltage current is passed between two tungsten electrodes through a
AWLIA0009GB
1. BCM M18, M20 (view with instrument
panel removed) 2. IPDM E/R E122, E123, E124 3. Combination switch M28
4. Combination meter M23, M24
ALLIA0379ZZ
Revision: March 2010 2008 QX56

EXL-8
< FUNCTION DIAGNOSIS >
HEADLAMP
mixtureof xenon (an inert gas) and certain other metal halides. In addition to added lighting power, electronic
controlof the power supply gives the headlamps stable quality and tone color.Following are some of the many
advantages of the xenon type headlamp.
• The light produced by the headlamps is a white color comparable to sunlight that is easy on the eyes.
• Light output is nearly double that of halogen headlamps, affording increased area of illumination.
• The light features a high relative spectral distribution at wavelengths to which the human eye is most sensi-tive. This means that even in the rain, more light is reflected back from the road surface toward the vehi-
cle,for added visibility.
• Power consumption is approximately 25 percent less than halogen headlamps, reducing battery load..
HIGH BEAM OPERATION/FLASH-TO-PASS OPERATION
With the lighting switch in the 2ND position and placed in HIGH position, the BCM receives input requesting
the headlamp high beams to illuminate. The flash to pass feature can be used any time and also sends a sig-
nal to the BCM. This input is communicated to t he IPDM E/R via the CAN communication lines. The CPU of
the combination meter controls the ON/OFF status off the HIGH BEAM indicator. The CPU of the IPDM E/R
controls the headlamp high relay coil which supplies power to the high beam headlamps.
The combination meter receives a high beam request signal (ON) via the CAN communication lines and turns
the high beam indicator lamp ON.
COMBINATION SWITCH READING FUNCTION
Refer to BCS-7, "System Description".
AUTO LIGHT OPERATION
Refer to EXL-11, "System Description".
Revision: March 2010 2008 QX56

EXL-10
< FUNCTION DIAGNOSIS >
DAYTIME LIGHT SYSTEM
Component Description
INFOID:0000000001547101
After starting the engine with the parking brake released and the lighting switch in the OFF or 1ST position, the
headlamp high beam automatically turns on at a reduced intensity. With the lighting switch in the 2nd position
or with autolamps ON, the headlamps function the same as conventional light systems.
OPERATION
The BCM monitors inputs from the parking brake switch and the combination switch to determine when to acti-
vate the daytime light system. The BCM sends a dayti me light request to the IPDM E/R via the CAN commu-
nication lines. The IPDM E/R grounds the daytime light relay which in turn, provides power to the ground side
of the LH high beam lamp. Power flows backward through the LH high beam lamp to the IPDM E/R, through
the high beam fuses, through the RH high beam lamp circuit to the RH high beam lamp and on to ground. The
high beam lamps are wired in series which causes them to illuminate at a reduced intensity.
1. IPDM E/R E119, E122, E123, E124 2. Parking brake switch M11 3. BCM M18, M20 (view with instrument
panel removed)
4. Daytime running light relay E103 5. Combination switch M28 6. Combination meter M24
Revision: March 2010 2008 QX56

FRONT FOG LAMPEXL-15
< FUNCTION DIAGNOSIS >
C
DE
F
G H
I
J
K
M A
B
EXL
N
O P
FRONT FOG LAMP
System DiagramINFOID:0000000001547106
System DescriptionINFOID:0000000001547107
The front fog lamps are activated with the lighting switch (combination switch). The lighting switch signal to
the BCM is monitored with the BCM combination switch reading function. When the fog lamps are turned ON
with the lighting switch, the BCM sends a front fog lamp request signal via CAN communication lines to the
IPDM E/R. The IPDM E/R grounds the front fog la mp relay coil to activate the front fog lamps.
Component Parts LocationINFOID:0000000001547108
Component DescriptionINFOID:0000000001547109
FRONT FOG LAMP OPERATION
When the lighting switch is in front fog lamp ON posit ion and also in 1ST or 2ND position or AUTO position
(headlamp is ON), the BCM detects FR FOG ON and t he HEAD LAMP1, 2 ON or the AUTO LIGHT ON. The
BCM sends a front fog lamp request ON signal via the CAN communication lines to the IPDM E/R. The IPDM
E/R then turns ON the front fog lamp re lay sending power to the front fog lamps.
COMBINATION SWITCH READING FUNCTION
Refer to BCS-7, "System Description".
JPLIA0004GB
1. BCM M18, M20 (view with instrument
panel removed) 2. IPDM E/R E122, E123, E124 3. Combination switch M28
ALLIA0379ZZ
Revision: March 2010
2008 QX56

EXL-18
< FUNCTION DIAGNOSIS >
PARKING, LICENSE PLATE AND TAIL LAMPS
PARKING, LICENSE PLATE AND TAIL LAMPS
System DiagramINFOID:0000000001547114
System DescriptionINFOID:0000000001547115
PARKING, LICENCE PLATE AND TAIL LAMPS OPERATION
When the lighting switch is in 1ST position, BCM detects the LIGHTI NG SWITCH 1ST POSITION ON. The
BCM sends a parking light ON request via the CAN comm unication lines to the IPDM E/R. The IPDM E/R then
activates the tail lamp relay which sends power to the parking and instrument illumination circuits.
EXTERIOR LAMP BATTERY SAVER CONTROL
With the lighting switch (combination switch) in the 2nd position and the ignition switch is turned from ON or
ACC to OFF, the battery saver feature is activated.
Under this condition, the headlamps remain illuminated for 5 minutes unless the lighting switch position is
changed. If the lighting switch position is changed, then the headlamps are turned off.
This setting can be changed by CONSULT-III. Refer to EXL-23, "
EXTERNAL LAMP : CONSULT-III Function".
COMBINATION SWITCH READING FUNCTION
Refer to BCS-7, "System Description".
Component Parts LocationINFOID:0000000001547116
AWLIA0013GB
1. BCM M18, M20 (view with instrument
panel removed) 2. IPDM E/R E122, E124 3. Combination switch M28
ALLIA0379ZZ
Revision: March 2010
2008 QX56

PARKING, LICENSE PLATE AND TAIL LAMPS
EXL-19
< FUNCTION DIAGNOSIS >
C
D E
F
G H
I
J
K
M A
B
EXL
N
O P
Component DescriptionINFOID:0000000001547117
Part name Description
BCM • Recieves lighting switch requests via BCM combination switch
reading function.
• Sends parking light request signal to the IPDM E/R.
IPDM E/R Activates the tail lamp relay upon request of the BCM.
Combination switch (lighting switch) Outputs lighting requests to the BCM.
Revision: March 2010 2008 QX56

EXL-20
< FUNCTION DIAGNOSIS >
TRAILER TOW
TRAILER TOW
System DiagramINFOID:0000000006095108
System DescriptionINFOID:0000000006095109
TRAILER TAIL LAMP OPERATION
The trailer tail lamps are controlled by the trailer tow relay 1 located behind the left side of the instrument panel
(IP). With the combination switch in the 1st position, the BCM detects the LIGHTING SWITCH 1ST POSITION
ON. The BCM sends a parking light ON request via the CAN communication lines to the IPDM E/R. The IPDM
E/R then activates the tail lamp relay which activates the trailer tow relay 1 and sends power to the trailer con-
nector.
TRAILER TURN SIGNAL LAMP OPERATION
The trailer turn signal lamps are controlled by the BCM. When the turn signal switch is in the LH or RH position
with the ignition switch ON, the combination switch sends a signal to the BCM. The BCM detects the TURN
RH or TURN LH ON request. The BCM sends a control signal to the respective trailer turn relay which sends
power to the trailer connector.
TRAILER HAZARD LAMP OPERATION
The trailer hazard lamps are controlled by the BCM. W hen the hazard switch is pressed, the BCM detects the
the hazard ON request. The BCM then sends a control si gnal to both trailer turn relays which sends power to
the trailer connector.
TRAILER BRAKE LAMP OPERATION
The trailer brake lamps are controlled by the BCM. When the brake pedal is depressed, the combination meter
receives a stop lamp switch signal from the stop lamp switch. The combination meter then sends the brake
signal to the BCM via the CAN communication lines. The BCM then sends a control signal to both trailer turn
relays which sends power to the trailer connector.
AWLIA1764GB
Revision: March 2010 2008 QX56

TRAILER TOWEXL-21
< FUNCTION DIAGNOSIS >
C
DE
F
G H
I
J
K
M A
B
EXL
N
O P
Component Parts LocationINFOID:0000000006095110
Component DescriptionINFOID:0000000006095111
1. BCM M18, M19, M20 (view with instru- ment panel removed) 2. IPDM E/R E119, E122, E123, E124 3. Combination meter M23, M24
4. Combination switch M28 5. Trailer tow relay 1 M51 (view with
steering member removed) 6. Battery
7. Trailer turn relay LH E156 8. Trailer turn relay RH E157 9. Trailer tow relay 2 E140
10. Stop lamp switch E38
AWLIA1772ZZ
Part name Description
BCM • Receives lighting and turn signal requests from combination
switch.
• Receives stop lamp signal requests from combination meter via CAN communication.
• Sends lighting signal request to the IPDM E/R to control the tail
lamp relay via CAN communication.
• Sends turn/hazard/brake control signal to the trailer turn relays.
IPDM E/R Activates the tail lamp relay upon request from the BCM via CAN
communication.
Revision: March 2010
2008 QX56