2002 JEEP LIBERTY 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
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 takeout 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 trim
panel. 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
KJLAMPS/LIGHTING - EXTERIOR 8L - 7
LAMPS/LIGHTING - EXTERIOR (Continued)

BRAKE LAMPS
CONDITION POSSIBLE CAUSES CORRECTION
BRAKE LAMP DOES NOT
ILLUMINATE1. Faulty or missing fuse. 1. Test and replace brake lamp fuse as
required.
2. Faulty or missing bulb. 2. Test and replace brake lamp bulb as
required.
3. Faulty switch. 3. Test and replace brake lamp switch as
required.
4. Faulty ground circuit. 4. Test and repair brake lamp ground circuit
as required.
5. Faulty feed circuit. 5. Test and repair open brake lamp switch
output circuit as required.
BRAKE LAMP DOES NOT
EXTINGUISH1. Faulty switch. 1. Test and replace brake lamp switch as
required.
2. Faulty feed circuit. 2. Test and repair shorted brake lamp
switch output circuit as required.
DAYTIME RUNNING LAMPS
Before performing the following tests, determine
whether the headlamp low and high beams operate.If the headlamp high and low beams are also inoper-
ative, diagnose and repair that problem before
attempting to repair the Daytime Running Lamps.
CONDITION POSSIBLE CAUSES CORRECTION
DAYTIME RUNNING
LAMPS WILL NOT
ILLUMINATE1. High beam relay installed. 1. Remove high beam relay as required.
2. Faulty or missing DRL relay. 2. Replace DRL relay with a known good
unit and check operation. Replace DRL
relay as required.
3. Incorrect BCM programming. 3. Use a DRBIIITscan tool to check and
program correct country code into BCM as
required.
4. Faulty BCM inputs or outputs. 4. Use a DRBIIITscan tool to test the BCM
inputs or outputs. Refer to the appropriate
diagnostic information.
KJLAMPS/LIGHTING - EXTERIOR 8L - 9
LAMPS/LIGHTING - EXTERIOR (Continued)

HEADLAMPS
CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMP DOES NOT
ILLUMINATE1. Faulty or missing fuse. 1. Test and replace headlamp fuse as
required.
2. Faulty or missing bulb. 2. Test and replace headlamp bulb as
required.
3. Faulty or missing relay. 3. 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.)
4. Faulty switch. 4. Test and replace multi-function switch as
required.
5. Faulty ground circuit. 5. Test and repair open headlamp ground
circuit as required.
6. Faulty feed circuit. 6. Test and repair open headlamp low beam,
high beam, or DRL 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.
HEADLAMP DOES NOT
EXTINGUISH1. 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 feed circuit. 3. Test and repair shorted headlamp low
beam, high beam, or DRL 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.
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.
KJLAMPS/LIGHTING - EXTERIOR 8L - 11
LAMPS/LIGHTING - EXTERIOR (Continued)

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.
PARK LAMPS
CONDITION POSSIBLE CAUSES CORRECTION
PARK LAMP DOES NOT
ILLUMINATE1. Faulty or missing fuse. 1. Test and replace park lamp fuse as
required.
2. Faulty or missing bulb. 2. Test and replace park lamp bulb as
required.
3. Faulty or missing relay. 3. Test and replace park lamp relay as
required.
4. Faulty switch. 4. Test and replace multi-function switch as
required.
5. Faulty ground circuit. 5. Test and repair open park lamp ground
circuit as required.
6. Faulty feed circuit. 6. Test and repair open park 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.
8L - 12 LAMPS/LIGHTING - EXTERIORKJ
LAMPS/LIGHTING - EXTERIOR (Continued)

SPECIFICATIONS - LAMPS/LIGHTING -
EXTERIOR
BULB SPECIFICATIONS
LAMP BULB
Backup 3157 P27/7W
Brake 3157 P27/7W
Center High Mounted
Stop921/W16W
Front Fog 9145
Front Park 3157 P27/7W
Front Position W5W
Front Side Marker 168
Front Turn 3157 P27/7W
Headlamp (North
America)9007QL
Headlamp (Rest-Of-
World)H-4 W0W6
License Plate (North
America)168
License Plate (Rest-Of-
World)W5W
Rear Fog 3157 P27/7W
Rear Park/Tail 3157 P27/7W
Rear Turn 3157 P27/7W
Side Repeater W5W
BACKUP LAMP SWITCH
DESCRIPTION
Vehicles equipped with a manual transmission
have a normally open, spring-loaded plunger type
back-up lamp switch (Fig. 2). The backup lamp
switch is located in a threaded hole on the side of the
manual transmission housing, beneath the floor
panel of the vehicle. The backup lamp switch has a
threaded body and a hex formation near the plunger
end of the switch, and an integral connector recepta-
cle at the opposite end of the switch. When installed,
only the connector receptacle and the hex formation
are visible on the outside of the transmission hous-
ing. Vehicles with an optional electronic automatic
transmission have a Transmission Range Sensor
(TRS) that is used to perform several functions,
including that of the backup lamp switch. The TRS is
described in further detail elsewhere in this service
information. The backup lamp switch cannot be
adjusted or repaired and, if faulty or damaged, the
entire switch unit must be replaced.
OPERATION
The backup lamp switch controls the flow of bat-
tery current to the backup lamp bulbs at the back of
the vehicle through an output on the back-up lamp
feed circuit. The switch plunger is mechanically actu-
ated by the gearshift mechanism within the trans-
mission, which will depress the switch plunger and
close the switch contacts whenever the reverse gear
has been selected. The switch receives battery cur-
rent through a fuse in the Junction Block (JB) on a
fused ignition switch output (run) circuit whenever
the ignition switch is in the On position. A take out
of the engine wire harness connects the backup lamp
switch to the vehicle electrical system. The backup
lamp switch and circuits can be tested using conven-
tional diagnostic tools and methods.
DIAGNOSIS AND TESTING - BACKUP LAMP
SWITCH
(1) Disconnect and isolate the battery negative
cable.
(2) Raise and support the vehicle.
(3) Locate and disconnect the engine wire harness
connector for the backup lamp switch from the
switch connector receptacle.
(4) Check for continuity between the two terminal
pins in the backup lamp switch connector receptacle.
(a) With the gear selector lever in the Reverse
position, there should be continuity.
(b) With the gear selector lever in any position
other than Reverse, there should be no continuity.
Fig. 2 Backup Lamp Switch - Typical
1 - MANUAL TRANSMISSION
2 - BACKUP LAMP SWITCH
3 - ENGINE WIRE HARNESS
KJLAMPS/LIGHTING - EXTERIOR 8L - 15
LAMPS/LIGHTING - EXTERIOR (Continued)

stant battery voltage is supplied to the flasher so that it
can perform the hazard warning function, and ignition
switched battery voltage is supplied for the turn signal
function. The Integrated Circuit (IC) within the combi-
nation flasher contains the logic that controls the
flasher operation and the flash rate. The IC receives
separate sense ground inputs from the multi-function
switch for the right and left turn signals, and from the
hazard switch contacts or the BCM for the hazard
warning signals. A special design feature of the combi-
nation flasher allows it to9sense9that a turn signal cir-
cuit or bulb is not operating, and provide the driver an
indication of the condition by flashing the remaining
bulbs in the affected circuit at a higher rate (120 flash-
es-per-minute or higher). Conventional flashers either
continue flashing at their typical rate (heavy-duty type),
or discontinue flashing the affected circuit entirely
(standard-duty type).
Because of the active electronic elements within
the combination flasher, it cannot be tested with con-
ventional automotive electrical test equipment. If the
combination flasher is believed to be faulty, test the
turn signal and hazard warning system. Then
replace the hazard switch with a known good unit to
confirm system operation.
DAYTIME RUNNING LAMP
RELAY
DESCRIPTION
The Daytime Running Lamp (DRL) relay (Fig. 8) is
a solid state relay that is used only on vehicles man-
ufactured for sale in Canada. The DRL relay features
a die cast aluminum housing with integral cooling
fins that act as a heat sink for the solid state DRL
circuitry. Four male spade terminals extend from the
base of the relay through a potting material that
encloses and protects the DRL circuitry. Although the
DRL relay has four terminals that are laid out in a
footprint that is similar to that of a conventional
International Standards Organization (ISO) relay, a
standard ISO relay should never be installed in place
of the DRL relay. The DRL relay is installed in the
Junction Block (JB) on the driver side outboard end
of the instrument panel. Vehicles equipped with this
relay do not have a headlamp high beam relay
installed in the JB.
The DRL relay cannot be adjusted or repaired and,
if faulty or damaged, the unit must be replaced.
OPERATION
The Daytime Running Lamp (DRL) relay is a solid
state relay that controls the flow of battery current
to the high beam filaments of both headlamp bulbs
based upon a duty cycled control input received from
the Body Control Module (BCM) of vehicles equipped
with the DRL feature. By cycling the DRL relay out-
put, the BCM controls the illumination intensity of
the high beam filaments. The DRL relay terminals
are connected to the vehicle electrical system through
a connector receptacle in the Junction Block (JB).
The inputs and outputs of the DRL relay include:
²Battery Current Input- The DRL relay
receives battery current on a fused B(+) circuit from
a fuse in the Power Distribution Center (PDC).
²Ground Input- The DRL relay receives a path
to ground through a splice block located in the
instrument panel wire harness with an eyelet termi-
nal connector that is secured by a nut to a ground
stud on the driver side instrument panel end bracket
near the Junction Block (JB).
²Control Input- The DRL relay control input is
received from the BCM and/or the momentary optical
horn (flash-to-pass) output of the multi-function
switch through a high beam relay control circuit.
²Control Output- The DRL relay supplies bat-
tery current output to the headlamp high beam fila-
ments through the high beam relay output circuit.
Because of active electronic elements within the
DRL relay, it cannot be tested with conventional
automotive electrical test equipment. If the DRL
relay is believed to be faulty, replace the relay with a
known good unit to confirm system operation.
Fig. 8 Daytime Running Lamp Relay
1 - DRL RELAY
2 - HEAT SINK
3 - POTTING MATERIAL
4 - TERMINAL (4)
8L - 20 LAMPS/LIGHTING - EXTERIORKJ
COMBINATION FLASHER (Continued)

LIGHTING - EXTERIOR/FRONT LAMP UNIT -
REMOVAL).
(3) Firmly grasp the socket on the back of the
front lamp unit housing for the bulb that is being
removed (Fig. 18).
(4) Rotate the socket on the back of the front lamp
unit housing counterclockwise about 30 degrees.
(5) Pull the socket and bulb straight out of the
back of the front lamp unit housing.
(6) Pull the bulb straight out of the front lamp
unit socket.
INSTALLATION
CAUTION: Always use the correct bulb size and
type for replacement. An incorrect bulb size or type
may overheat and cause damage to the lamp, the
socket and/or the lamp wiring.
(1) Align the base of the bulb with the receptacle
in the front lamp unit socket.
(2) Push the bulb straight into the front lamp unit
socket until it is firmly seated.
(3) Align the socket and bulb with the socket open-
ing on the back of the front lamp unit housing (Fig.
18).
(4) Push the socket and bulb straight into the
front lamp unit housing until it is firmly seated.
(5) Rotate the socket on the back of the front lamp
unit housing clockwise about 30 degrees.
(6) Reinstall the front lamp unit into the front
bumper fascia. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/FRONT LAMP UNIT -
INSTALLATION).
(7) Reconnect the battery negative cable.
FRONT LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the screw that secures the outboard
end of the front lamp unit to the front bumper fascia
(Fig. 19).
(3) Pull the outboard end of the front lamp unit
away from the front bumper fascia far enough to dis-
Fig. 17 Front Fog Lamp Adjusting Screw
1 - FRONT BUMPER FASCIA
2 - ADJUSTING SCREW
3 - FRONT FOG LAMP UNIT
Fig. 18 Front Lamp Bulb Remove/Install
1 - FRONT LAMP UNIT
2 - SIDE MARKER SOCKET
3 - FRONT FASCIA
4 - HEADLAMP & DASH WIRE HARNESS
5 - MOUNTING TAB
6 - PARK/TURN SIGNAL SOCKET
Fig. 19 Front Lamp Unit Remove/Install
1 - FRONT LAMP UNIT
2 - FRONT BUMPER FASCIA
3 - SCREW (1)
KJLAMPS/LIGHTING - EXTERIOR 8L - 27
FRONT LAMP BULB (Continued)

engage the tab on the inboard end of the front lamp
unit housing from the receptacle in the fascia.
(4) Pull the front lamp unit away from the front
bumper fascia far enough to access and disconnect
the wire harness connector(s) for the front lamp unit
from the lamp socket pigtail wire(s).
(5) Remove the front lamp unit from the front
bumper fascia.
INSTALLATION
(1) Position the front lamp unit to the front
bumper fascia.
(2) Reconnect the wire harness connector(s) for the
front lamp unit to the lamp socket pigtail wire(s).
(3) Engage the tab on the inboard end of the front
lamp unit housing into the receptacle in the front
bumper fascia.
(4) Position the outboard end of the front lamp
unit housing to the front bumper fascia.
(5) Install and tighten the screw that secures the
outboard end of the front lamp unit housing to the
front bumper fascia (Fig. 19). Tighten the screw to 2
N´m (20 in. lbs.).
(6) Reconnect the battery negative cable.
FRONT POSITION LAMP BULB
REMOVAL
The front position lamps are integral to the head-
lamp units on vehicles manufactured for certain mar-
kets where these lamps are required.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the headlamp unit from the front grille
opening reinforcement. (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/HEADLAMP UNIT
- REMOVAL).
(3) Rotate the front position lamp socket near the
bottom of the headlamp unit housing counterclock-
wise about 30 degrees (Fig. 20).
(4) Pull the socket and bulb straight out of the
headlamp unit housing.
(5) Pull the bulb straight out of the front position
lamp socket.
INSTALLATION
The front position lamps are integral to the head-
lamp units on vehicles manufactured for certain mar-
kets where these lamps are required.CAUTION: Always use the correct bulb size and
type for replacement. An incorrect bulb size or type
may overheat and cause damage to the lamp, the
socket and/or the lamp wiring.
(1) Align the base of the bulb with the receptacle
in the front position lamp socket.
(2) Push the bulb straight into the front position
lamp socket until it is firmly seated.
(3) Align the socket and bulb with the socket open-
ing near the bottom of the headlamp unit housing
(Fig. 20).
(4) Push the socket and bulb straight into the
headlamp unit housing until it is firmly seated
(5) Rotate the front position lamp socket near the
bottom of the headlamp unit housing clockwise about
30 degrees.
(6) Reinstall the headlamp unit onto the grille
opening reinforcement. (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/HEADLAMP UNIT
- INSTALLATION).
(7) Reconnect the battery negative cable.
(8) Confirm proper headlamp unit alignment.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/HEADLAMP UNIT - ADJUSTMENTS).
Fig. 20 Front Position Lamp Bulb Remove/Install
1 - HEADLAMP HOUSING
2 - SOCKET
3 - BULB
8L - 28 LAMPS/LIGHTING - EXTERIORKJ
FRONT LAMP UNIT (Continued)