Page 945 of 2305

received by the cluster from the Engine Control Mod-
ule (ECM) over the Controller Area Network (CAN)
data bus. The tachometer is an air core magnetic
unit that receives battery current on the instrument
cluster electronic circuit board when the instrument
cluster detects that the ignition switch is in the On
position. The cluster is programmed to move the
gauge needle back to the low end of the scale after
the ignition switch is turned to the Off position. The
instrument cluster circuitry controls the gauge nee-
dle position and provides the following features:
²Engine Speed Message- Each time the cluster
receives an engine speed message from the ECM it
will calculate the correct engine speed reading and
position the gauge needle at that relative speed posi-
tion on the gauge scale. The gauge needle will con-
tinually be repositioned at the relative engine speed
position on the gauge scale until the engine stops
running, or until the ignition switch is turned to the
Off position, whichever occurs first.
²Communication Error- If the cluster fails to
receive an engine speed message, it will hold the
gauge needle at the last indication for about three
seconds, or until the ignition switch is turned to the
Off position, whichever occurs first. After three sec-
onds, the gauge needle will return to the left end of
the gauge scale.
The ECM continually monitors the crankshaft posi-
tion sensor to determine the engine speed. The ECM
then sends the proper engine speed messages to the
instrument cluster. For proper diagnosis of the
crankshaft position sensor, the ECM, the CAN data
bus, or the electronic message inputs to the instru-
ment cluster that control the tachometer, a diagnos-
tic scan tool is required. Refer to the appropriate
diagnostic information.
TRACTION CONTROL INDICA-
TOR
DESCRIPTION
A traction control (ASR) indicator is standard
equipment on all instrument clusters. The traction
control indicator is located near the center of the
speedometer in the instrument cluster. The traction
control indicator consists of an ª!º (exclamation point)
imprinted within a triangular cutout in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. An
amber Light Emitting Diode (LED) behind the cutout
in the opaque layer of the overlay causes the excla-
mation point to appear silhouetted against an amber
field through the translucent outer layer of the over-
lay when the indicator is illuminated from behind by
the LED, which is soldered onto the instrument clus-ter electronic circuit board. The traction control indi-
cator is serviced as a unit with the instrument
cluster.
OPERATION
The traction control (ASR) indicator gives several
indications to the vehicle operator concerning the
operating status of the traction control (ASR) system.
The traction control indicator is controlled by a tran-
sistor on the instrument cluster circuit board based
upon cluster programming and electronic messages
received by the cluster from the Controller Anti-lock
Brake (CAB) over the Controller Area Network
(CAN) data bus. The traction control indicator Light
Emitting Diode (LED) is completely controlled by the
instrument cluster logic circuit, and that logic will
only allow this indicator to operate when the instru-
ment cluster detects that the ignition switch is in the
On position. Therefore, the LED will always be off
when the ignition switch is in any position except
On. The LED only illuminates when it is provided a
path to ground by the instrument cluster transistor.
The instrument cluster will turn on the traction con-
trol indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the traction control indica-
tor is illuminated for about two seconds as a bulb
test.
²Traction Control (ASR) Indicator Lamp-On
Message- Each time the cluster receives a traction
control indicator lamp-on message from the CAB, the
indicator will be illuminated. This indicator can be
flashed on and off, or illuminated solid, as dictated
by the CAB message. The indicator is illuminated
solid when the traction control system has been deac-
tivated; and is flashed when the traction control is
activated or when the driven wheels lose traction
with the traction control deactivated. The indicator
remains flashing or illuminated solid until the clus-
ter receives a lamp-off message from the CAB, or
until the ignition switch is turned to the Off position,
whichever occurs first.
The CAB continually monitors the traction control
(ASR) switch and the four wheel speed sensors to
determine the correct operating mode for the traction
control system. The CAB then sends the proper
lamp-on or lamp-off messages to the instrument clus-
ter. See the owner's manual in the vehicle glove box
for more information on the features, use, activation
and deactivation of the traction control (ASR) system.
For proper diagnosis of the traction control system,
the CAB, the CAN data bus, or the electronic mes-
sage inputs to the instrument cluster that control the
traction control indicator, a diagnostic scan tool is
required. Refer to the appropriate diagnostic infor-
mation.
8J - 26 INSTRUMENT CLUSTERVA
Page 946 of 2305

TRACTION CONTROL MAL-
FUNCTION INDICATOR
DESCRIPTION
A traction control (ASR) malfunction indicator is
standard equipment on all instrument clusters. The
traction control malfunction indicator is located near
the lower edge of the instrument cluster, to the right
of the multi-function indicator display. The traction
control malfunction indicator consists of an icon that
graphically depicts a tire and two skid marks
imprinted within a rectangular cutout in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. An
amber Light Emitting Diode (LED) behind the cutout
in the opaque layer of the overlay causes the icon to
appear silhouetted against an amber field through
the translucent outer layer of the overlay when the
indicator is illuminated from behind by the LED,
which is soldered onto the instrument cluster elec-
tronic circuit board. The traction control malfunction
indicator is serviced as a unit with the instrument
cluster.
OPERATION
The traction control (ASR) malfunction indicator
gives the vehicle operator an indication when the
traction control system is faulty or inoperative. This
indicator is controlled by a transistor on the instru-
ment cluster circuit board based upon cluster pro-
gramming and electronic messages received by the
cluster from the Controller Antilock Brake (CAB)
over the Controller Area Network (CAN) data bus.
The traction control malfunction indicator Light
Emitting Diode (LED) is completely controlled by the
instrument cluster logic circuit, and that logic will
only allow this indicator to operate when the instru-
ment cluster detects that the ignition switch is in the
On position. Therefore, the LED will always be off
when the ignition switch is in any position except
On. The LED only illuminates when it is provided a
path to ground by the instrument cluster transistor.
The instrument cluster will turn on the traction con-
trol malfunction indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the traction control indica-
tor is illuminated as a bulb test until the engine is
started.
²Traction Control (ASR) Malfunction Indica-
tor Lamp-On Message- Each time the cluster
receives a traction control malfunction indicator
lamp-on message from the CAB, the indicator will be
illuminated. The indicator remains illuminated until
the cluster receives a lamp-off message from the
CAB, or until the ignition switch is turned to the Off
position, whichever occurs first.The CAB continually monitors the traction control
(ASR) system circuits and sensors to decide whether
the system is in good operating condition. The CAB
then sends the proper lamp-on or lamp-off messages
to the instrument cluster. If the CAB sends a
lamp-on message after the bulb test, it indicates that
the CAB has detected a system malfunction and that
the traction control (ASR) system has become inoper-
ative. The CAB will store a Diagnostic Trouble Code
(DTC) for any malfunction it detects. In addition, if
the traction control malfunction indicator is illumi-
nated, the CAB will deactivate an activated traction
control system and engine power output may be
reduced. See the owner's manual in the vehicle glove
box for more information on the features, use, activa-
tion and deactivation of the traction control (ASR)
system. For proper diagnosis of the traction control
system, the CAB, the CAN data bus, or the electronic
message inputs to the instrument cluster that control
the traction control malfunction indicator, a diagnos-
tic scan tool is required. Refer to the appropriate
diagnostic information.
TURN SIGNAL INDICATOR
DESCRIPTION
Two turn signal indicators, one right and one left,
are standard equipment on all instrument clusters.
The turn signal indicators are located near the upper
edge of the instrument cluster, one to each side of the
speedometer. Each turn signal indicator consists of a
arrow-shaped cutout of the International Control and
Display Symbol icon for ªTurn Warningº in the
opaque layer of the instrument cluster overlay. The
dark outer layer of the overlay prevents these icons
from being clearly visible when they are not illumi-
nated. A green Light Emitting Diode (LED) behind
each turn signal indicator cutout in the opaque layer
of the overlay causes the icon to appear in green
through the translucent outer layer of the overlay
when the indicator is illuminated from behind by the
LED, which is soldered onto the instrument cluster
electronic circuit board. The turn signal indicators
are serviced as a unit with the instrument cluster.
OPERATION
The turn signal indicators give an indication to the
vehicle operator that the turn signal (left or right
indicator flashing) or hazard warning (both left and
right indicators flashing) have been selected and are
operating. These indicators are controlled by transis-
tors on the instrument cluster electronic circuit board
based upon the cluster programming and a hard
wired input received by the cluster from the turn sig-
nal relay through the turn signal and hazard warn-
ing switch circuitry of the multi-function switch on
VAINSTRUMENT CLUSTER 8J - 27
Page 947 of 2305

the left and right turn signal circuits. Each turn sig-
nal indicator Light Emitting Diode (LED) is com-
pletely controlled by the instrument cluster logic
circuit, and that logic will allow this indicator to
operate whenever the instrument cluster receives a
battery current input on the fused B(+) circuit.
Therefore, each LED can be illuminated regardless of
the ignition switch position. The LED only illumi-
nates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the turn signal indicators for the follow-
ing reasons:
²Turn Signal Input- Each time the cluster
detects a turn signal input from the turn signal relay
through the closed turn signal switch circuitry of the
multi-function switch on the hard wired left or right
turn signal circuit, the requested turn signal lamps
and turn signal indicator will be flashed on and off,
and a contactless relay soldered onto the cluster elec-
tronic circuit board will produce a clicking sound to
emulate a conventional turn signal flasher. The turn
signals and the turn signal indicators continue to
flash on and off until the turn signal switch circuitry
of the multi-function switch is opened, or until the
ignition switch is turned to the Off position, which-
ever occurs first.
²Hazard Warning Input- Each time the cluster
detects a hazard warning input from the turn signal
relay through the closed hazard warning switch cir-
cuitry of the multi-function switch on the hard wired
left and right turn signal circuits, all of the turn sig-
nal lamps and both turn signal indicators will be
flashed on and off, and a contactless relay soldered
onto the cluster electronic circuit board will produce
a clicking sound to emulate a conventional hazard
warning flasher. The turn signals and the turn signal
indicators continue to flash on and off until the haz-
ard warning switch circuitry of the multi-function
switch is opened.
An electronic wipers, turn signals and engine start
control module located within the fuse block beneath
the steering column monitors the turn signal circuits
and controls the flash rate of the turn signal relay.
The instrument cluster continually monitors the
right and left turn signal circuits to determine the
proper turn signal and hazard warning indicator
operation, then flashes the proper turn signal indica-
tors and the contactless relay on and off accordingly.
The multi-function switch, the turn signal relay and
the left and right turn signal circuits to the instru-
ment cluster can be diagnosed using conventional
diagnostic tools and methods. For proper diagnosis of
the wipers, turn signals and engine start control
module within the fuse block or the instrument clus-
ter circuitry that controls the turn signal indicators
and the contactless relay, a diagnostic scan tool is
required. Refer to the appropriate diagnostic infor-
mation.WAIT - TO - START INDICATOR
DESCRIPTION
A wait-to-start indicator is standard equipment in
all instrument clusters. The wait-to-start indicator is
located near the lower edge of the instrument cluster,
to the right of the multi-function indicator display.
The wait-to-start indicator consists of the Interna-
tional Control and Display Symbol icon for ªDiesel
Preheatº imprinted within a rectangular cutout in
the opaque layer of the instrument cluster overlay.
The dark outer layer of the overlay prevents the indi-
cator from being clearly visible when it is not illumi-
nated. An amber Light Emitting Diode (LED) behind
the cutout in the opaque layer of the overlay causes
the icon to appear silhouetted against an amber field
through the translucent outer layer of the overlay
when the indicator is illuminated from behind by the
LED, which is soldered onto the instrument cluster
electronic circuit board. The wait-to-start indicator is
serviced as a unit with the instrument cluster.
OPERATION
The wait-to-start indicator gives an indication to
the vehicle operator when the diesel engine glow
plugs are energized in their pre-heat operating mode.
This indicator is controlled by a transistor on the
instrument cluster circuit board based upon cluster
programming and electronic messages received by
the cluster from the Engine Control Module (ECM)
over the Controller Area Network (CAN) data bus.
The wait-to-start indicator Light Emitting Diode
(LED) is completely controlled by the instrument
cluster logic circuit, and that logic will only allow
this indicator to operate when the instrument cluster
detects that the ignition switch is in the On position.
Therefore, the LED will always be off when the igni-
tion switch is in any position except On. The LED
only illuminates when it is provided a path to ground
by the instrument cluster transistor. The instrument
cluster will turn on the wait-to-start indicator for the
following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the wait-to-start indicator
is illuminated for about two seconds as a bulb test.
²Wait-To-Start Lamp-On Message- Each time
the cluster receives a wait-to-start lamp-on message
from the ECM indicating that the diesel engine glow
plugs are energized in their pre-heat operating mode,
the wait-to-start indicator will be illuminated. The
indicator remains illuminated until the cluster
receives a wait-to-start lamp-off message indicating
that the pre-heat mode of the glow plugs has been
completed, until the ECM detects that the engine is
running, or until the ignition switch is turned to the
Off position, whichever occurs first.
8J - 28 INSTRUMENT CLUSTERVA
Page 948 of 2305

The ECM continually monitors the engine coolant
temperature sensor to determine when the glow
plugs need to be energized in their pre-heat operat-
ing mode. The ECM then sends the proper wait-to-
start lamp-on and lamp-off messages to the
instrument cluster. If the instrument cluster turns on
the indicator after the engine is started, it may indi-
cate that a malfunction has occurred and that the
engine glow control system requires service. The
ECM will store a Diagnostic Trouble Code (DTC) for
any malfunction it detects. For proper diagnosis of
the engine coolant temperature sensor, the engine
glow control system and circuits, the ECM, the CAN
data bus, or the electronic message inputs to the
instrument cluster that control the wait-to-start indi-
cator, a diagnostic scan tool is required. Refer to the
appropriate diagnostic information.
WASHER FLUID INDICATOR
DESCRIPTION
A washer fluid indicator is standard equipment on
all instrument clusters. However, this indicator is
only functional on vehicles equipped with an optional
washer fluid level switch integral to the washer
pump/motor unit on the washer reservoir. The
washer fluid indicator is located near the lower edge
of the instrument cluster, to the right of the multi-
function indicator display. The washer fluid indicator
consists of the International Control and Display
Symbol icon for ªWindshield Washer Fluidº imprinted
within a rectangular cutout in the opaque layer of
the instrument cluster overlay. The dark outer layer
of the overlay prevents the indicator from being
clearly visible when it is not illuminated. An amber
Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
silhouetted against an amber field through the trans-
lucent outer layer of the overlay when the indicator
is illuminated from behind by the LED, which is sol-
dered onto the instrument cluster electronic circuit
board. The washer fluid indicator is serviced as a
unit with the instrument cluster.
OPERATION
The washer fluid indicator gives an indication to
the vehicle operator that the fluid level in the washer
reservoir is low. This indicator is controlled by the
instrument cluster circuit board based upon cluster
programming and a hard wired input from the
optional washer fluid level switch that is integral to
the washer pump/motor unit. The washer fluid indi-
cator is completely controlled by the instrument clus-
ter logic circuit, and that logic will only allow this
indicator to operate when the instrument cluster
detects that the ignition switch is in the On position.
Therefore, the indicator will always be off when theignition switch is in any position except On. The indi-
cator only illuminates when it is switched to ground
by the instrument cluster circuitry. The instrument
cluster will turn on the washer fluid indicator for the
following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the brake wear indicator is
illuminated by the instrument cluster for about two
seconds as a bulb test.
²Washer Fluid Level Switch Input- Each time
the cluster detects ground on the washer fluid switch
sense circuit (washer fluid level switch closed =
washer fluid level low) while the ignition switch is in
the On position, the washer fluid indicator is illumi-
nated. The indicator remains illuminated until the
washer fluid level switch input to the cluster is an
open circuit (washer fluid level switch open = washer
fluid level acceptable), or until the ignition switch is
turned to the Off position, whichever occurs first.
The instrument cluster continually monitors the
washer fluid level switch to determine the level of
the washer fluid. The instrument cluster logic applies
a delay strategy to this input to reduce the negative
effect that fluid sloshing within the reservoir can
have on reliable indicator operation. The washer
fluid level switch and circuit can be diagnosed using
conventional diagnostic tools and methods. For
proper diagnosis of the instrument cluster circuitry
that controls the washer fluid indicator, a diagnostic
scan tool is required. Refer to the appropriate diag-
nostic information.
WATER - IN - FUEL INDICATOR
DESCRIPTION
A water-in-fuel indicator is standard equipment in
all instrument clusters. The water-in-fuel indicator is
located near the lower edge of the instrument cluster,
to the left of the multi-function indicator display. The
water-in-fuel indicator consists of the International
Control and Display Symbol icon for ªWater In Fuelº
imprinted within a rectangular cutout in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. An
amber Light Emitting Diode (LED) behind the cutout
in the opaque layer of the overlay causes the icon to
appear silhouetted against an amber field through
the translucent outer layer of the overlay when the
indicator is illuminated from behind by the LED,
which is soldered onto the instrument cluster elec-
tronic circuit board. The water-in-fuel indicator is
serviced as a unit with the instrument cluster.
OPERATION
The water-in-fuel indicator gives an indication to
the vehicle operator when there is excessive water
VAINSTRUMENT CLUSTER 8J - 29
Page 949 of 2305

detected in the fuel filter. This indicator is controlled
by a transistor on the instrument cluster circuit
board based upon the cluster programming and elec-
tronic messages received by the cluster from the
Engine Control Module (ECM) over the Controller
Area Network (CAN) data bus. The water-in-fuel
indicator Light Emitting Diode (LED) is completely
controlled by the instrument cluster logic circuit, and
that logic will only allow this indicator to operate
when the instrument cluster detects that the ignition
switch is in the On position. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On. The LED only illuminates when it is
provided a path to ground by the instrument cluster
transistor. The instrument cluster will turn on the
water-in-fuel indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the water-in-fuel indicator
is illuminated for about seven seconds as a bulb test.
²Water-In-Fuel Lamp-On Message- Each time
the cluster receives a water-in-fuel lamp-on message
from the ECM indicating that there is excessive
water in the fuel filter with the engine running, the
water-in-fuel indicator will be illuminated. The indi-
cator remains illuminated until the cluster receives a
water-in-fuel lamp-off message, or until the ignition
switch is turned to the Off position, whichever occurs
first.
The ECM continually monitors the water-in-fuel
sensor to determine whether there is excessive water
in the fuel filter. The ECM then sends the proper
water-in-fuel lamp-on and lamp-off messages to the
instrument cluster. If the water-in-fuel indicator
remains illuminated with the engine running, excess
water should be drained from the fuel filter. If the
indicator remains illuminated with the engine run-
ning after the water has been drained from the fuel
filter, it may indicate that a malfunction has
occurred in the water-in-fuel sensor or circuits. The
ECM will store a Diagnostic Trouble Code (DTC) for
any malfunction it detects. For proper diagnosis of
the water-in-fuel sensor and circuits, the ECM, the
CAN data bus, or the electronic message inputs to
the instrument cluster that control the water-in-fuel
indicator, a diagnostic scan tool is required. Refer to
the appropriate diagnostic information.
8J - 30 INSTRUMENT CLUSTERVA
Page 950 of 2305

LAMPS
TABLE OF CONTENTS
page page
LAMPS/LIGHTING - EXTERIOR............... 1LAMPS/LIGHTING - INTERIOR............... 28
LAMPS / LIGHTING - EXTERIOR
TABLE OF CONTENTS
page page
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION..........................2
OPERATION............................3
SPECIFICATIONS - LAMPS/LIGHTING -
EXTERIOR...........................5
BACKUP LAMP BULB
REMOVAL.............................5
INSTALLATION..........................6
BRAKE LAMP SWITCH
REMOVAL.............................6
INSTALLATION..........................7
ADJUSTMENTS
ADJUSTMENT.........................7
BRAKE/PARK LAMP BULB
REMOVAL.............................7
INSTALLATION..........................8
CENTER HIGH MOUNTED STOP LAMP BULB
REMOVAL.............................8
INSTALLATION..........................8
CENTER HIGH MOUNTED STOP LAMP UN
REMOVAL.............................8
INSTALLATION..........................9
CLEARANCE LAMP BULB
REMOVAL.............................9
INSTALLATION..........................9
CLEARANCE LAMP UNIT
REMOVAL.............................9
INSTALLATION..........................9
DAYTIME RUNNING LAMP RELAY
REMOVAL.............................10
INSTALLATION.........................10
FOG LAMP BULB
REMOVAL.............................10
INSTALLATION.........................11
FOG LAMP RELAY
REMOVAL.............................11
INSTALLATION.........................12
FOG LAMP SWITCH
REMOVAL.............................12
INSTALLATION.........................13FRONT LAMP UNIT
REMOVAL.............................13
INSTALLATION.........................13
ADJUSTMENTS
ADJUSTMENT - FRONT LAMP UNIT.......14
FRONT POSITION LAMP BULB
REMOVAL.............................14
INSTALLATION.........................15
FRONT TURN/PARK/SIDE MARKER LAMP
BULB
REMOVAL.............................15
INSTALLATION.........................16
HEADLAMP LEVELING MOTOR
REMOVAL.............................16
INSTALLATION.........................17
HEADLAMP LEVELING SWITCH
REMOVAL.............................17
INSTALLATION.........................18
HIGH BEAM HEADLAMP BULB
REMOVAL.............................18
INSTALLATION.........................19
LICENSE PLATE LAMP BULB
REMOVAL.............................19
INSTALLATION.........................19
LICENSE PLATE LAMP UNIT
REMOVAL.............................19
INSTALLATION.........................19
LOW BEAM HEADLAMP BULB
REMOVAL.............................20
INSTALLATION.........................20
MULTI-FUNCTION SWITCH
REMOVAL.............................21
INSTALLATION.........................21
PARK BRAKE SWITCH
REMOVAL.............................21
INSTALLATION.........................22
REAR SIDE MARKER LAMP BULB
REMOVAL.............................22
INSTALLATION.........................22
VALAMPS 8L - 1
Page 951 of 2305

REAR TURN LAMP BULB
REMOVAL.............................23
INSTALLATION.........................23
REPEATER LAMP BULB
REMOVAL.............................23
INSTALLATION.........................24
REPEATER LAMP UNIT
REMOVAL.............................24INSTALLATION.........................25
TAIL LAMP UNIT
REMOVAL.............................25
INSTALLATION.........................26
TURN SIGNAL RELAY
REMOVAL.............................26
INSTALLATION.........................26
LAMPS / LIGHTING - EXTE-
RIOR
DESCRIPTION
The exterior lighting system for this model
includes the following exterior lamps:
²Backup Lamps- The backup (or reverse) lamps
are integral to the tail lamp units mounted to the
back of the quarter panel on each side of the tailgate
at the rear of the vehicle.
²Brake Lamps- The brake (or stop) lamps
include a bulb and reflector that are integral to the
tail lamp units mounted to the back of the quarter
panel on each side of the tailgate opening, and the
Center High Mounted Stop Lamp (CHMSL) that is
centered on the rear edge of the roof panel above the
tailgate opening.
²Daytime Running Lamps- Vehicles manufac-
tured for sale in Canada have a Daytime Running
Lamps (DRL) relay that illuminates the low beam
headlamp bulbs whenever the engine is running.
²Fog Lamps- Fog lamp bulbs and reflectors are
included in both front lamp units of vehicles
equipped with this option.
²Hazard Warning Lamps- The hazard warning
lamps include all of the right and left turn signal and
repeater lamps.
²Headlamps- Separate low beam and high
beam headlamp bulbs are installed in the front lamp
unit on each side of the front grille opening. A head-
lamp leveling actuator motor is also integral to each
front lamp unit.
²Park Lamps- The park lamps include the front
park/side marker lamps and front position lamps
that are integral to the front lamp units mounted on
either side of the front grille opening, as well as the
rear park lamps and rear side marker lamps that are
integral to the tail lamp units mounted to the back of
the quarter panel on each side of the tailgate open-
ing. Included in the park lamps circuit are two rear
license plate lamp units mounted on the left rear
tailgate door. The park lamps may also include
optional clearance lamps, which are located on each
side of a vehicle that is so equipped.
²Turn Signal Lamps- The turn signal lamps
include the front turn lamps that are integral to the
front lamp units, the rear turn lamps that are inte-
gral to the tail lamp units, and a repeater lampmounted to each front fender just above the front
wheel opening.
Other components of the exterior lighting system
for this model include:
²Brake Lamp Switch- A plunger-type brake
lamp switch is located on the steering column sup-
port bracket under the instrument panel and actu-
ated by the brake pedal arm.
²Daytime Running Lamp Relays- Vehicles
manufactured for sale in Canada have two Daytime
Running Lamps (DRL) relays. Dedicated right and
left side relays illuminate the low beam headlamp
bulb installed in each front lamp unit whenever the
engine is running. These relays are located in dedi-
cated vehicle wire harness connectors within the
driver side front seat riser.
²Fog Lamp Relay- Vehicles equipped with the
optional fog lamps have a fog lamp relay located in a
dedicated vehicle wire harness connector within the
driver side front seat riser.
²Fog Lamp Switch- A fog lamp switch is
mounted in the instrument cluster bezel, below the
cluster and outboard of the steering column on vehi-
cles equipped with this option.
²Headlamp Leveling Motor- A headlamp lev-
eling actuator motor is located on the back of each
headlamp housing and adjusts both the low beam
headlamp, high beam headlamp, and fog lamp (if
equipped) reflector frames in unison.
²Headlamp Leveling Switch- A thumbwheel
actuated headlamp leveling switch is mounted in the
instrument cluster bezel, below the cluster and out-
board of the steering column.
²Multi-Function Switch- The multi-function
switch is located on the top of the steering column,
just below the steering wheel. The multi-function
switch is connected directly to the fuse block located
below the steering column through an integral inter-
face connector. Only the left (lighting), right (wiper)
control stalks and the hazard warning switch button
for the multi-function switch are visible, the remain-
der of the switch is concealed beneath the steering
column shrouds. The multi-function switch includes a
left (lighting) control stalk and a right (wiper) control
stalk. The left control stalk is dedicated to providing
almost all of the driver controls for the exterior light-
ing system.
²Trailer Tow Connector- Vehicles equipped
with a factory-approved, field-installed trailer towing
8L - 2 LAMPS/LIGHTING - EXTERIORVA
Page 952 of 2305

electrical package have a heavy duty 7-way trailer
tow connector installed in a bracket on the trailer
hitch receiver. This package includes a 7-way to
4-way connector adapter unit.
²Trailer Tow Control Module- Vehicles
equipped with a factory-approved, field-installed
trailer towing electrical package have a trailer tow
brake/turn control module located within the driver
side front seat riser that controls the brake lamp and
turn signal lamp outputs to the trailer lighting cir-
cuits.
²Turn Signal Relay- A turn signal relay is
installed in the fuse block located on the underside of
the steering column behind a fuse access panel in the
steering column opening cover on the instrument
panel. The electronic circuitry of the wipers, turn sig-
nals and engine start control module within the fuse
block controls the turn signal relay.
²Wipers, Turn Signals, Engine Start Control
Module- The wipers, turn signals and engine start
control module is integral to the fuse block located on
the underside of the steering column behind a fuse
access panel in the steering column opening cover on
the instrument panel. This module includes active
electronic elements that control the operation of the
turn signal relay based upon inputs from the multi-
function switch and feedback from the turn signal
circuits. (Refer to 8 - ELECTRICAL/POWER DISTRI-
BUTION/FUSE BLOCK - DESCRIPTION).
Hard wired circuitry connects the exterior lighting
system components to the electrical system of the
vehicle. These hard wired circuits are integral to sev-
eral wire harnesses, which are routed throughout the
vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the exterior lighting
system components through the use of a combination
of soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
OPERATION
Following are paragraphs that briefly describe the
operation of each of the major exterior lighting sys-
tems. The hard wired circuits and components of the
exterior lighting systems may be diagnosed and
tested using conventional diagnostic tools and proce-
dures. However, conventional diagnostic methods
may not prove conclusive in the diagnosis of the wip-
ers, turn signals and engine start control module
located within the fuse block underneath the steering
column, the ElectroMechanical Instrument Cluster
(EMIC), the Engine Control Module (ECM), or theController Area Network (CAN) data bus network.
The most reliable, efficient, and accurate means to
diagnose the electronic module within the fuse block,
the EMIC, the ECM, and the CAN data bus network
inputs and outputs related to the various exterior
lighting systems requires the use of a diagnostic scan
tool. Refer to the appropriate diagnostic information.
BACKUP LAMPS
The backup (or reverse) lamps have a path to
ground received at all times through the vehicle wire
harness from a ground point located on the frame
near the left end of the tailgate sill. The backup
lamps receive battery current on the backup lamp
supply circuit only when the backup lamp switch cir-
cuit of the Transmission Range Sensor (TRS) integral
to the gear shifter assembly is closed by the gear
shifter mechanism.
BRAKE LAMPS
The brake (or stop) lamps have a path to ground at
all times through the vehicle wire harness from a
ground point located on the frame near the left end
of the tailgate sill. The Center High Mounted Stop
Lamp (CHMSL) has a path to ground at all times
through the vehicle wire harness from a ground point
on the left side of the dash panel. The brake lamps
and CHMSL receive battery current on the brake
lamp switch output circuit when the brake lamp
switch is closed by the brake pedal arm.
DAYTIME RUNNING LAMPS
Vehicles manufactured for sale in Canada illumi-
nate the low beam headlamp bulb when the engine is
running and the exterior lamps are turned off. This
feature is enabled by the right and left Daytime Run-
ning Lamps (DRL) relays. When the DRL relays are
de-energized, they provide fused battery current from
the circuit K26 relay to the headlamp low beams.
When the headlamps are turned On using the left
(lighting) control stalk of the multi-function switch
the DRL relays are energized, which returns control
of the headlamps to the headlamp switch circuitry of
the multi-function switch. The circuit K26 relay is
energized by the ElectroMechanical Instrument Clus-
ter (EMIC) whenever it receives an electronic mes-
sage from the Engine Control Module (ECM) over the
Controller Area Network (CAN) data bus indicating
that the engine is running. The DRL and circuit K26
relays are installed in a relay bracket located below
the forward edge of the driver side front seat cushion
within the driver side front seat riser.
FRONT FOG LAMPS
Vehicles equipped with optional front fog lamps
have a front fog lamp relay installed in a relay
bracket located below the forward edge of the driver
side front seat cushion within the driver side front
VALAMPS/LIGHTING - EXTERIOR 8L - 3