signal JEEP LIBERTY 2002 KJ / 1.G Repair Manual

path to the switches using another internal driver
through the courtesy lamp load shed circuit. The
BCM provides a battery saver (load shedding) feature
for all courtesy lamps, which will automatically turn
these lamps off if they are left on for more than
about eight minutes with the ignition switch in the
Off position.
PANEL LAMPS DIMMER CIRCUIT The panel
lamps dimmer circuit includes the ElectroMechanical
Instrument Cluster (EMIC), heater-air conditioner
control, hazard switch and, depending upon the
selected vehicle options, ash receiver, and automatic
transmission range indicator illumination lamps. All
lamps in the panel lamps dimmer circuit are pro-
vided a path to ground at all times through a hard
wired ground circuit. These lamps illuminate based
upon inputs to the Body Control Module (BCM) from
the exterior lighting control knob and the interior
lighting control ring on the left (lighting) control
stalk of the multi-function switch. The control knob
on the left control stalk of the multi-function switch
selects the exterior lights, while the control ring
selects the panel lamps intensity (dimming) level.
When the exterior lighting is turned On, the BCM
energizes the park lamp relay and provides an elec-
tronic dimming level message to the ElectroMechani-
cal Instrument Cluster (EMIC), the radio, and the
Compass Mini-Trip Computer (CMTC) over the Pro-
grammable Communications Interface (PCI) data
bus. The energized park lamp relay provides a hard
wired battery current signal input to the EMIC on
the park lamp relay output circuit. The EMIC
responds to these inputs by supplying a 12-volt Pulse
Width Modulated (PWM) output to all of the incan-
descent lamps in the panel lamps dimmer circuit
over the fused panel lamps dimmer switch signal cir-
cuit. This shared PWM output synchronizes the
selected illumination intensity level of all of the
incandescent lamps in the panel lamps dimmer cir-
cuit.
The EMIC and the radio each use the electronic
dimming level message from the BCM to control and
synchronize the illumination intensity of their own
Vacuum Fluorescent Display (VFD), while the CMTC
uses the dimming level message to control the illumi-
nation intensity of both its VFD and its incandescent
lighting. In addition, when the control ring on the
left (lighting) control stalk of the multi-function
switch is moved to the Parade Mode detent position,
all of the VFDs are illuminated at their full intensity
levels for increased visibility when the vehicle is
driven during daylight hours with the exterior lights
turned On.DIAGNOSIS AND TESTING - LAMPS/LIGHTING
- INTERIOR
The hard wired circuits and components of the
interior lighting system may be diagnosed and tested
using conventional diagnostic tools and procedures.
However, conventional diagnostic methods may not
prove conclusive in the diagnosis of the Body Control
Module (BCM), the ElectroMechanical Instrument
Cluster (EMIC), or the Programmable Communica-
tions Interface (PCI) data bus network. The most
reliable, efficient, and accurate means to diagnose
the BCM, the EMIC, and the PCI data bus network
inputs and outputs related to the various interior
lighting systems requires the use of a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
When diagnosing the interior lighting circuits,
remember that high generator output can burn out
bulbs rapidly and repeatedly; and, that dim or flick-
ering bulbs can be caused by low generator output or
poor battery condition. If one of these symptoms is a
problem on the vehicle being diagnosed, be certain to
diagnose and repair the battery and charging system
as required. Also keep in mind that a good ground is
necessary for proper lighting operation. If a lighting
problem is being diagnosed that involves multiple
symptoms, systems, or components the problem can
often be traced to a loose, corroded, or open ground.
For complete circuit diagrams, refer to the appropri-
ate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
8L - 68 LAMPS/LIGHTING - INTERIORKJ
LAMPS/LIGHTING - INTERIOR (Continued)

PANEL LAMPS DIMMER CIRCUIT
CONDITION POSSIBLE CAUSES CORRECTION
A SINGLE LAMP DOES
NOT ILLUMINATE1. Faulty or missing bulb. 1. Test and replace lamp bulb as required.
2. Faulty ground circuit. 2. Test and repair lamp ground circuit as
required.
3. Faulty feed circuit. 3. Test and repair open fused panel lamps
dimmer switch signal circuit as required.
A SINGLE LAMP DOES
NOT EXTINGUISH1. Faulty feed circuit. 1. Test and repair shorted fused panel
lamps dimmer switch signal circuit as
required.
ALL LAMPS DO NOT
ILLUMINATE1. Faulty fused park lamp relay
output circuit.1. Test and repair open fused park lamp
relay output circuit as required.
2. Faulty or missing park
lamp relay.2. Test and replace park lamp relay as
required.
3. Faulty fused panel lamps dimmer
switch signal circuit.3. Test and repair open fused panel lamps
dimmer switch signal circuit as required.
4. Faulty Body Control Module
(BCM), BCM input, or BCM output.4. Use a DRBIIITscan tool to test the BCM,
its inputs, and its outputs. Refer to the
appropriate diagnostic information.
5. Faulty ElectroMechanical
Instrument Cluster (EMIC), EMIC
input, or EMIC output.5. Use a DRBIIITscan tool to test the
EMIC, its inputs, and its outputs. Refer to
the appropriate diagnostic information.
6. Faulty multi-function switch. 6. Test and replace the multi-function switch
as required.
ALL LAMPS EXCEPT
CLUSTER ILLUMINATION
DO NOT EXTINGUISH1. Faulty feed circuit. 1. Test and repair shorted fused panel
lamps dimmer switch signal circuit as
required.
8L - 70 LAMPS/LIGHTING - INTERIORKJ
LAMPS/LIGHTING - INTERIOR (Continued)

LICENSE PLATE LAMP BULB
REMOVAL.............................44
INSTALLATION.........................45
LICENSE PLATE LAMP UNIT
REMOVAL.............................45
INSTALLATION.........................46
MULTI-FUNCTION SWITCH
DESCRIPTION.........................46
OPERATION...........................48
DIAGNOSIS AND TESTING - MULTI-
FUNCTION SWITCH...................50
REMOVAL.............................53
INSTALLATION.........................53
PARK LAMP RELAY
DESCRIPTION.........................54
OPERATION...........................54
DIAGNOSIS AND TESTING - PARK LAMP
RELAY..............................55
REMOVAL.............................55
INSTALLATION.........................56
REAR FOG LAMP RELAY
DESCRIPTION.........................56
OPERATION...........................57
DIAGNOSIS AND TESTING - REAR FOG
LAMP RELAY.........................57
REMOVAL.............................58
INSTALLATION.........................58
REAR LAMP BULB
REMOVAL.............................59
INSTALLATION.........................59
REAR LAMP UNIT
REMOVAL.............................59
INSTALLATION.........................60
REPEATER LAMP BULB
REMOVAL.............................60INSTALLATION.........................60
REPEATER LAMP UNIT
REMOVAL.............................61
INSTALLATION.........................61
TRAILER TOW CONNECTOR
REMOVAL.............................61
INSTALLATION.........................61
TRAILER TOW RELAY
DESCRIPTION.........................62
OPERATION...........................62
DIAGNOSIS AND TESTING - TRAILER TOW
RELAY..............................62
REMOVAL.............................63
INSTALLATION.........................63
TRAILER TOW WIRING
DESCRIPTION.........................64
LAMP BAR
DESCRIPTION.........................65
OPERATION...........................65
DIAGNOSIS AND TESTING - LAMP BAR.....65
STANDARD PROCEDURE - LAMP BAR
AIMING.............................65
REMOVAL
REMOVAL - LAMP BAR.................65
REMOVAL - LAMP.....................66
INSTALLATION
INSTALLATION - LAMP BAR.............66
INSTALLATION - LAMP.................66
LAMP BAR SWITCH
DESCRIPTION.........................67
REMOVAL.............................67
INSTALLATION.........................67
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION
The exterior lighting system for this model
includes the following exterior lamps (Fig. 1):
²Backup Lamps- The backup (or reverse) lamps
are integral to the rear 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 lamp that is integral to the rear lamp units
mounted to the back of the quarter panel on each
side of the tailgate, and the Center High Mounted
Stop Lamp (CHMSL) that is centered on the rear
edge of the roof panel above the flip-up glass opening
at the rear of the vehicle.
²Daytime Running Lamps- Vehicles manufac-
tured for sale in Canada illuminate the high beam
filament in each headlamp bulb serves as the Day-
time Running Lamps (DRL).²Front Fog Lamps- Optional front fog lamps
include a single round front fog lamp unit with an
adjustable reflector and a removable bulb that is
secured behind a dedicated opening on each forward-
facing end of the front bumper fascia.
²Hazard Warning Lamps- The hazard warning
lamps include all of the right and left turn signal
lamps.
²Headlamps- A single round headlamp housing
with a fixed lens, an adjustable reflector, and a single
removable halogen bulb is secured to the grille open-
ing panel on each side of the grille opening at the
front of the vehicle. In certain markets where
required, a headlamp leveling actuator motor is
included on each headlamp.
²Park Lamps- The park lamps include the front
park lamps and front side marker lamps that are
integral to the front lamp units mounted at each end
of the bumper fascia at the front of the vehicle, as
well as the rear park lamps and rear side marker
lamps that are integral to the rear lamp units
8Ls - 2 LAMPSKJ

mounted to the back of the quarter panel on each
side of the tailgate at the rear of the vehicle. The
park lamps include a license plate lamp or lamps,
depending upon the requirements of the market for
which the vehicle is manufactured. Vehicles with a
license plate tub located near the left end of the rear
bumper fascia have a single lamp, while vehicles
with a license plate module located on the spare tire
carrier have two license plate lamps. In certain mar-
kets where required, a front position lamp that is
integral to each headlamp unit is illuminated instead
of the front park lamps and front side marker lamps
in the park lamps circuit; and, a rectangular, red
reflector is located on the rear bumper fascia just
inboard and below each rear lamp unit.
²Rear Fog Lamps- Rear fog lamps are avail-
able only in certain markets where they are required
equipment. The rear fog lamps are integral to the
rear lamp units mounted to the back of the quarter
panel on each side of the tailgate at the rear of the
vehicle.
²Turn Signal Lamps- The turn signal lamps
include the front turn signal and front side marker
lamps that are integral to the front lamp units
mounted at each end of the bumper fascia at the
front of the vehicle, as well as rear turn signal lamps
that are integral to the rear lamp units mounted to
the back of the quarter panel on each side of the tail-
gate at the rear of the vehicle. In certain markets
where required, a repeater lamp unit mounted to
each front fender just behind the front wheel opening
is illuminated instead of the front side marker lamp
in each turn signal lamp circuit.
Other components of the exterior lighting system
for this model include:
²Combination Flasher- An electronic combina-
tion flasher is integral to the hazard warning switch
in the center of the instrument panel.
²Backup Lamp Switch- Vehicles equipped with
a manual transmission have a plunger-type backup
lamp switch located on the transmission housing. A
Transmission Range Sensor (TRS) integral to the
solenoid pack on the valve body of the optional elec-
tronic automatic transmission performs the backup
lamp switch function on models that are so equipped.
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.²Body Control Module- The Body Control
Module (BCM) is located on the Junction Block (JB)
under the driver side outboard end of the instrument
panel. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/BODY CONTROL MODULE
- DESCRIPTION).
²Daytime Running Lamp Relay- Vehicles
manufactured for sale in Canada use a solid state
Daytime Running Lamps (DRL) relay installed in the
Junction Block (JB) instead of the conventional high
beam relay.
²Front Fog Lamp Relay- Vehicles equipped
with the optional front fog lamps have a front fog
lamp relay located in the Junction Block (JB).
²Hazard Switch- The hazard switch is located
near the center of the instrument panel and includes
the integral electronic combination flasher circuitry
for the hazard warning system and the turn signal
system.
²Headlamp Leveling Motor- A headlamp lev-
eling actuator motor is located on the back of each
headlamp housing of vehicles manufactured for cer-
tain markets where this equipment is required.
²Headlamp Leveling Switch- A thumbwheel
actuated headlamp leveling switch is mounted in the
driver side inboard instrument panel trim bezel of
vehicles manufactured for certain markets where this
equipment is required.
²High Beam Relay- A high beam relay is
located in the Junction Block (JB) of all vehicles
except those that are manufactured for sale in Can-
ada. Canadian vehicles have a solid state Daytime
Running Lamps (DRL) relay in the JB instead of the
high beam relay.
²Low Beam Relay- A low beam relay is located
in the Junction Block (JB) of all vehicles.
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 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 con-
trols for both the exterior and interior lighting sys-
tems.
²Park Lamp Relay- A park lamp relay is
located in the Junction Block (JB) of all vehicles.
²Rear Fog Lamp Relay- Vehicles manufac-
tured for certain markets where rear fog lamps are
required equipment have a rear fog lamp relay
located in the Junction Block (JB).
1 - HEADLAMP UNIT (2)
2 - REPEATER LAMP UNIT (2)
3 - FRONT POSITION LAMP (2)
4 - FRONT LAMP UNIT (2)5 - FRONT FOG LAMP (2)
6 - CENTER HIGH MOUNTED STOP LAMP UNIT
7 - REAR LAMP UNIT
8 - LICENSE PLATE LAMP UNIT
8Ls - 4 LAMPSKJ
LAMPS/LIGHTING - EXTERIOR (Continued)

²Trailer Tow Adapter- Vehicles equipped with
a factory-installed trailer towing package have an
adapter provided that adapts the factory-installed
heavy duty 7-way trailer tow connector to a conven-
tional 4-way light duty connector.
²Trailer Tow Connector- Vehicles equipped
with a factory-installed trailer towing package have a
heavy duty 7-way trailer tow connector installed in a
bracket on the trailer hitch receiver.
²Trailer Tow Relays- Vehicles equipped with a
factory-installed trailer towing package have a con-
nector bank containing four relays located behind the
right quarter trim panel and over the right rear
wheel housing. The four relays are used to supply
fused ignition switch output (run), brake lamps, right
turn signal, and left turn signal outputs to a trailer
through the trailer tow wiring and connectors.
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 Body
Control Module (BCM), the ElectroMechanical
Instrument Cluster (EMIC), the Powertrain Control
Module (PCM), or the Programmable Communica-
tions Interface (PCI) data bus network. The most
reliable, efficient, and accurate means to diagnose
the BCM, the EMIC, the PCM, and the PCI data bus
network inputs and outputs related to the various
exterior lighting systems requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.BACKUP LAMPS
The backup (or reverse) lamps have a path to
ground at all times through their connection to the
rear lighting wire harness from a take out of the rear
body wire harness with an eyelet terminal connector
that is secured by a ground screw to the base of the
right D-pillar behind the quarter trim panel. The
backup lamps receive battery current from a fused
ignition switch output (run) fuse in the Junction
Block (JB) on the back-up lamp feed circuit only
when the backup lamp switch (manual transmission),
or backup lamp switch circuit of the Transmission
Range Sensor (TRS - electronic automatic transmis-
sion) is closed by the gearshift mechanism within the
transmission.
BRAKE LAMPS
The brake (or stop) lamps have a path to ground at
all times through their connection to the rear light-
ing wire harness from a take out of the rear body
wire harness with an eyelet terminal connector that
is secured by a screw to the base of the right D-pillar
behind the quarter trim panel. The Center High
Mounted Stop Lamp (CHMSL) has a path to ground
at all times through its connection to the rear body
wire harness from a take out of the rear body wire
harness with an eyelet terminal connector that is
secured by a ground screw to the driver side D-pillar
(left side D-pillar for left-hand drive, right side D-pil-
lar for right-hand drive) behind the quarter trim
panel. The brake lamps and CHMSL receive battery
current from a fused B(+) fuse in the Junction Block
(JB) on the brake lamp switch output circuit only
when the brake lamp switch circuit of the brake
lamp switch is closed by the brake pedal arm.
DAYTIME RUNNING LAMPS
Vehicles manufactured for sale in Canada illumi-
nate the high beam filament at a reduced intensity
when the engine is running and the exterior lamps
are turned off. This feature is enabled by the Body
Control Module (BCM) and a solid state Daytime
Running Lamps (DRL) relay, which is installed in the
Junction Block (JB) and the high beam relay is omit-
ted. When the BCM monitors an engine speed signal
of greater than 450 RPM and the status of the exte-
rior lighting switch input from the multi-function
switch is Off, the BCM duty cycles the DRL relay to
produce illumination of the headlamp high beam fil-
aments at a reduced intensity. The BCM also pro-
vides normal headlamp high beam operation through
the DRL relay on vehicles so equipped. When the
DRL relay is energized, it provides battery current
from a fused B(+) fuse in the JB to the headlamp
high beam filament through the DRL relay output
circuit.
KJLAMPS8Ls-5
LAMPS/LIGHTING - EXTERIOR (Continued)

FRONT FOG LAMPS
Vehicles equipped with optional front fog lamps
have a premium Body Control Module (BCM), a front
fog lamp relay installed in the Junction Block (JB),
and a front fog lamp switch integral to the left (light-
ing) control stalk of the multi-function switch. The
front fog lamps have a path to ground at all times
through their connection to the front fascia wire har-
ness from two take outs of the headlamp and dash
wire harness with eyelet terminal connectors that
are secured by ground screws to the left inner fender
shield in the engine compartment. The BCM controls
front fog lamp operation by monitoring the exterior
lighting switch input from the multi-function switch,
then energizing or de-energizing the front fog lamp
relay control coil; and, by sending the appropriate
electronic message to the instrument cluster over the
Programmable Communications Interface (PCI) data
bus to turn the front fog lamp indicator on or off.
When the front fog lamp relay is energized, it pro-
vides battery current from a fused B(+) fuse in the
JB to the front fog lamps through the front fog lamp
relay output circuit. The BCM provides a battery
saver (load shedding) feature for the front fog lamps,
which will turn these lamps off if they are left on for
more than about eight minutes with the ignition
switch in the Off position. In certain markets where
required, the front fog lamps are also turned off by
the BCM whenever the headlamp high beams are
selected. Each front fog lamp includes an integral
adjustment screw to be used for static aiming the fog
lamp beams.
HAZARD WARNING LAMPS
With the hazard switch in the On position, the
hazard warning system is activated causing the haz-
ard switch button illumination lamp, the right and
left turn signal indicators, and the right and left turn
signal lamps to flash on and off. When the hazard
warning system is activated, the circuitry within the
hazard switch and electronic combination flasher
unit will repeatedly energize and de-energize two
internal relays that switch battery current from a
fused B(+) fuse in the Junction Block (JB) to the
right side and left side turn signal indicators, and
turn signal lamps through the right and left turn sig-
nal circuits. The flashing of the hazard switch button
illumination lamp is performed internally by the haz-
ard switch and combination flasher unit circuit
board. The hazard warning lamps can also be ener-
gized by the Body Control Module (BCM) through a
hazard lamp control circuit input to the hazard
switch and combination flasher unit.HEADLAMPS
The headlamp system includes the Body Control
Module (BCM), a low beam relay installed in the
Junction Block (JB), a high beam relay installed in
the JB (except Canada), a solid state Daytime Run-
ning Lamps (DRL) relay installed in the JB (Canada
only), and the exterior lighting (headlamp and dim-
mer) switches integral to the left (lighting) control
stalk of the multi-function switch. The headlamp
bulbs have a path to ground at all times through
their connection to the grille opening reinforcement
wire harness from two take outs of the headlamp and
dash wire harness with eyelet terminal connectors
that are secured by ground screws to the left inner
fender shield in the engine compartment. The BCM
controls the headlamp operation by monitoring the
exterior lighting switch inputs from the multi-func-
tion switch, then energizing or de-energizing the con-
trol coils of the low beam relay, the high beam relay,
or the solid state circuitry of the DRL relay; and, by
sending the appropriate electronic message to the
instrument cluster over the Programmable Commu-
nications Interface (PCI) data bus to turn the high
beam indicator on or off. When each respective relay
is energized, it provides battery current from a fused
B(+) fuse in the Power Distribution Center (PDC)
through a relay (low beam, high beam, or DRL) out-
put circuit and four separate fuses in the JB through
individual fused right and left, low and high beam
output circuits to the appropriate headlamp bulb fil-
aments. The BCM provides a battery saver (load
shedding) feature for the headlamps, which will turn
these lamps off if they are left on for more than
about eight minutes with the ignition switch in the
Off position; and, a headlamp delay feature with a
DRBIIItscan tool programmable delay interval.
Each headlamp includes an integral adjustment
screw to be used for static aiming of the headlamp
beams.
HEADLAMP LEVELING
In certain markets where required, a headlamp
leveling system is provided on the vehicle. The head-
lamp leveling system includes unique headlamp units
equipped with a headlamp leveling actuator motor,
and a rotary thumbwheel actuated headlamp leveling
switch on the instrument panel. The headlamp level-
ing system allows the headlamp beams to be
adjusted to one of four vertical positions to compen-
sate for changes in inclination caused by the loading
of the vehicle suspension. The actuator motors are
mechanically connected through an integral pushrod
to an adjustable headlamp reflector. The headlamp
leveling switch is a resistor multiplexed unit that
provides one of four voltage outputs to the headlamp
leveling motors. The headlamp leveling motors will
8Ls - 6 LAMPSKJ
LAMPS/LIGHTING - EXTERIOR (Continued)

move the headlamps to the selected position based
upon the voltage input received from the switch. The
headlamp leveling motors and switch have a path to
ground at all times. The headlamp leveling compo-
nents operate on battery current received through
the fused park lamp relay output circuit so that the
system will only operate when the exterior lighting is
turned on.
PARK LAMPS
The park lamps system includes the Body Control
Module (BCM), a park lamp relay installed in the
Junction Block (JB), and the exterior lighting switch
integral to the left (lighting) control stalk of the
multi-function switch. The front park lamp and side
marker or, if equipped, the front position lamp bulbs
each have a path to ground at all times through their
connections to the grille opening reinforcement wire
harness from two take outs of the headlamp and
dash wire harness with eyelet terminal connectors
that are secured by ground screws to the left inner
fender shield in the engine compartment. The rear
park lamp bulbs and license plate lamp have a path
to ground at all times through their connection to the
rear lighting wire harness from a take out of the rear
body wire harness with an eyelet terminal connector
that is secured by a ground screw to the base of the
right D-pillar behind the quarter trim panel. The
BCM controls the park lamp operation by monitoring
the exterior lighting switch inputs from the multi-
function switch, then energizing or de-energizing the
control coil of the park lamp relay. When the park
lamp relay is energized, it provides battery current
from a fused B(+) fuse in the Power Distribution
Center (PDC) through a park lamp relay output cir-
cuit and a separate fuse in the JB through a fused
park lamp relay output circuit to the appropriate
lamp bulb filaments. The BCM provides a battery
saver (load shedding) feature for the park lamps,
which will turn these lamps off if they are left on for
more than about eight minutes with the ignition
switch in the Off position.
REAR FOG LAMPS
Rear fog lamps are installed on vehicles manufac-
tured for certain markets where they are required.
The rear fog lamp system includes a premium Body
Control Module (BCM), a rear fog lamp relay
installed in the Junction Block (JB), and a rear fog
lamp switch integral to the left (lighting) control
stalk of the multi-function switch. The rear fog lamps
have a path to ground at all times through their con-
nection to the rear lighting wire harness from a take
out of the rear body wire harness with an eyelet ter-
minal connector that is secured by a ground screw to
the base of the right D-pillar behind the quarter trimpanel. The BCM controls rear fog lamp operation by
monitoring the exterior lighting switch input from
the multi-function switch, then energizing or de-ener-
gizing the rear fog lamp relay control coil; and, by
sending the appropriate electronic message to the
instrument cluster over the Programmable Commu-
nications Interface (PCI) data bus to turn the rear
fog lamp indicator on or off. When the rear fog lamp
relay is energized, it provides battery current from a
fused B(+) fuse in the JB to the rear fog lamps
through the rear fog lamp relay output circuit. The
BCM provides a battery saver (load shedding) feature
for the rear fog lamps, which will turn these lamps
off if they are left on for more than about eight min-
utes with the ignition switch in the Off position.
TURN SIGNAL LAMPS
When the left control stalk of the multi-function
switch is moved up (right turn) or down (left turn),
the turn signal system is activated causing the
selected right or left turn signal indicator, and right
or left turn signal lamps to flash on and off. When
the turn signal system is activated, the circuitry
within the turn signal switch and the hazard switch/
electronic combination flasher unit will repeatedly
energize and de-energize one of two internal relays
that switch battery current from a fused ignition
switch output (run) fuse in the Junction Block (JB) to
the right side or left side turn signal indicators and
turn signal lamps through the right or left turn sig-
nal circuits. The ElectroMechanical Instrument Clus-
ter (EMIC) chime tone generator will generate an
audible turn signal cancel warning each time the
vehicle is driven for a distance of about 3.2 kilome-
ters (about two miles) with a turn signal indicator
flashing. The EMIC uses Programmable Communica-
tions Interface (PCI) data bus distance messages
from the Powertrain Control Module (PCM) and a
hard wired input from the turn signal switch cir-
cuitry of the multi-function switch to determine when
to sound the turn signal cancel warning.
DIAGNOSIS AND TESTING - LAMPS/LIGHTING
- EXTERIOR
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 Body
Control Module (BCM), the ElectroMechanical
Instrument Cluster (EMIC), the Powertrain Control
Module (PCM), or the Programmable Communica-
tions Interface (PCI) data bus network. The most
reliable, efficient, and accurate means to diagnose
the BCM, the EMIC, the PCM, and the PCI data bus
network inputs and outputs related to the various
KJLAMPS8Ls-7
LAMPS/LIGHTING - EXTERIOR (Continued)

FRONT FOG LAMPS
CONDITION POSSIBLE CAUSES CORRECTION
FRONT FOG LAMP DOES
NOT ILLUMINATE1. Faulty or missing fuse. 1. Test and replace front fog lamp fuse as
required.
2. Faulty or missing bulb. 2. Test and replace front fog lamp bulb as
required.
3. Faulty or missing relay. 3. Test and replace front fog lamp relay as
required.
4. Faulty switch. 4. Test and replace multi-function switch as
required.
5. Faulty ground circuit. 5. Test and repair front fog lamp ground
circuit as required.
6. Faulty feed circuit. 6. Test and repair open front fog lamp relay
output circuit as required.
7. Faulty BCM inputs or outputs. 7. Use a DRBIIITscan tool to test the BCM
inputs and outputs. Refer to the appropriate
diagnostic information.
FRONT FOG LAMP DOES
NOT EXTINGUISH1. Faulty relay. 1. Test and replace front fog lamp relay as
required.
2. Faulty switch. 2. Test and replace multi-function switch as
required.
3. Faulty feed circuit. 3. Test and repair shorted front fog lamp
relay output circuit as required.
4. Faulty BCM inputs or outputs. 4. Use a DRBIIITscan tool to test the BCM
inputs and outputs. Refer to the appropriate
diagnostic information.
HAZARD WARNING LAMPS
Before performing the following tests, confirm
whether the left and right turn signals operate satis-
factorily. If the turn signals are inoperative or oper-ate improperly, diagnose and repair that problem
before attempting to repair the Hazard Warning
Lamps.
CONDITION POSSIBLE CAUSES CORRECTION
HAZARD WARNING
LAMPS DO NOT FLASH1. Faulty or missing fuse. 1. Test and replace hazard warning fuse as
required.
2. Faulty ground circuit. 2. Test and repair hazard switch ground
circuit as required.
3. Faulty feed circuit. 3. Test and repair open hazard switch fused
B(+) circuit as required.
4. Faulty switch/flasher. 4. Replace hazard switch/combination
flasher with a known good unit and check
operation. Replace hazard switch/
combination flasher unit if required.
8Ls - 10 LAMPSKJ
LAMPS/LIGHTING - EXTERIOR (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS WILL NOT
SWITCH FROM HIGH TO
LOW BEAMS, OR FROM
LOW TO HIGH BEAMS1. Faulty relay. 1. Test and replace low beam or high beam
relay as required. (Note: Vehicles with a
DRL relay do not use a high beam relay.
The DRL relay cannot be tested. Replace
DRL relay with a known good unit and
check operation. Replace DRL relay as
required.)
2. Faulty switch. 2. Test and replace multi-function switch as
required.
3. Faulty BCM inputs or outputs. 3. Use a DRBIIITscan tool to test the BCM
inputs and outputs. Refer to the appropriate
diagnostic information.
HEADLAMP LEVELING
Before performing the following tests, confirm
whether the park lamps operate satisfactorily. If thepark lamps are inoperative, diagnose and repair that
problem before attempting to repair the Headlamp
Leveling System.
CONDITION POSSIBLE CAUSES CORRECTION
ONE LEVELING MOTOR
IS INOPERATIVE1. Faulty ground circuit. 1. Test and repair open leveling motor
ground circuit as required.
2. Faulty feed circuit. 2. Test and repair open leveling motor feed
circuit as required.
3. Faulty signal circuit. 3. Test and repair open headlamp adjust
signal circuit as required.
4. Faulty motor. 4. Test and replace headlamp leveling
motor as required.
BOTH LEVELING
MOTORS ARE
INOPERATIVE1. Faulty switch ground circuit. 1. Test and repair open leveling switch
ground circuit as required.
2. Faulty motor ground circuit. 2. Test and repair open leveling motor
ground circuit as required.
3. Faulty switch feed circuit. 3. Test and repair open leveling switch feed
circuit as required.
4. Faulty motor feed circuit. 4. Test and repair open leveling motor feed
circuit as required.
5. Faulty signal circuit. 5. Test and repair open or shorted leveling
motor signal circuit as required.
6. Faulty switch. 6. Test and replace leveling switch as
required.
7. Faulty motors. 7. Test and replace leveling motors as
required.
8Ls - 12 LAMPSKJ
LAMPS/LIGHTING - EXTERIOR (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
REAR FOG LAMP DOES
NOT EXTINGUISH1. Faulty relay. 1. Test and replace rear fog lamp relay as
required.
2. Faulty switch. 2. Test and replace multi-function switch as
required.
3. Faulty feed circuit. 3. Test and repair shorted rear fog lamp
relay output circuit as required.
4. Faulty BCM inputs or outputs. 4. Use a DRBIIITscan tool to test the BCM
inputs and outputs. Refer to the appropriate
diagnostic information.
TURN SIGNAL LAMPS
CONDITION POSSIBLE CAUSES CORRECTION
ONE TURN SIGNAL LAMP
DOES NOT ILLUMINATE1. Faulty or missing bulb. 1. Test and replace turn signal bulb as
required.
2. Faulty ground circuit. 2. Test and repair open ground circuit as
required.
3. Faulty feed circuit. 3. Test and repair open right or left turn
signal circuit as required.
ALL RIGHT SIDE AND/OR
ALL LEFT SIDE TURN
SIGNAL LAMPS DO NOT
FLASH1. Faulty sense circuit. 1. Test and repair open right or left turn
switch sense circuit as required.
2. Faulty switch. 2. Test and replace multi-function switch as
required.
3. Faulty flasher. 3. Replace hazard switch/combination
flasher with a known good unit and check
operation. Replace hazard switch/
combination flasher unit as required.
4. Faulty signal circuit. 4. Test and repair open right or left turn
signal circuit as required.
ALL RIGHT SIDE OR ALL
LEFT SIDE TURN
SIGNALS FLASH TOO
RAPIDLY (MORE THAN
100 FLASHES PER
MINUTE)1. Faulty or missing bulb. 1. Test and replace faulty bulb as required.
2. Faulty ground circuit. 2. Test and repair open ground circuit as
required.
3. Faulty signal circuit 3. Test and repair open right or left turn
signal circuit as required.
4. Faulty flasher. 4. Replace hazard switch/combination
flasher with a known good unit and check
operation. Replace hazard switch/
combination flasher unit as required.
8Ls - 14 LAMPSKJ
LAMPS/LIGHTING - EXTERIOR (Continued)