2002 JEEP LIBERTY Heat

HAZARD SWITCH
DESCRIPTION
The hazard switch is integral to the hazard switch
module, which is secured near the center of instrument
panel just above the radio (Fig. 21). Only the hazard
switch button is visible through a dedicated, round, bev-
eled opening on the outer surface of the instrument
panel between the two center panel outlets of the heater
and air conditioning system. A red, stencil-like Interna-
tional Control and Display Symbol icon for ªHazard
Warningº identifies the hazard switch button. On the
opposite end of the black, molded plastic hazard switch
module housing from the switch button is an integral
connector receptacle and a stamped steel mounting
bracket with two latch feature tabs that extend down-
ward, while a short dowel-like alignment pin is integral
to each side of the housing just below the switch button.
The switch module is connected to the vehicle electrical
system through a dedicated take out and connector of
the instrument panel wire harness. Within the hazard
switch module housing is the hazard switch circuitry
and an electronic circuit board with the integral combi-
nation flasher circuitry. The electronic combination
flasher circuitry performs both the hazard flasher and
turn signal flasher functions.
The hazard switch module cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The hazard switch button is slightly recessed in the
instrument panel when the switch is in the Off position,
and latches at a position that is flush with the outer
surface of the instrument panel when in the On posi-tion. The hazard switch module produces an audible
clicking sound that emulates the sound of a conven-
tional flasher whenever the turn signals or the hazard
warning system are activated. The hazard switch mod-
ule receives battery current on a fused B(+) circuit from
a fuse in the Junction Block (JB) at all times for oper-
ation of the hazard warning, and on a fused ignition
switch output (run) circuit from another fuse in the JB
whenever the ignition switch is in the On position for
operation of the turn signals. The module receives a
path to ground through a splice block located in the
instrument panel wire harness with an eyelet terminal
connector that is secured by a nut to a ground stud on
the driver side instrument panel end bracket near the
JB. Inputs to and outputs from the hazard switch mod-
ule include:
²Panel Lamps Dimmer Input- A non-service-
able incandescent bulb soldered onto the hazard
switch module circuit board provides illumination of
the switch button when the exterior lighting is
turned On through an input received on the fused
panel lamps dimmer switch signal circuit. However,
this bulb flashes on and off at full intensity whenever
the hazard switch button is in the On position,
regardless of the status of the exterior lighting.
²Hazard Switch Input- The combination
flasher circuitry of the hazard switch module receives
an internal ground input from the hazard switch to
request hazard flasher operation.
²Multi-Function Switch Input- The combina-
tion flasher circuitry of the hazard switch module
receives separate ground inputs from the turn signal
switch circuitry of the multi-function switch on right
and left turn switch sense circuits to request right or
left turn signal flasher operation.
²Body Control Module Input- The Body Con-
trol Module (BCM) can request hazard flasher opera-
tion by providing a ground path to the combination
flasher circuitry of the hazard switch module through
a hazard lamp control circuit.
²Turn Signal Output- The combination flasher
circuitry within the hazard switch module responds
to the flasher request inputs by energizing and
de-energizing two miniature relays on the module
circuit board. These relays control the switch output
through the right and left turn signal circuits. One
relay controls the right lamps, while the other con-
trols the left.
Because of active electronic elements within the
hazard switch module, it cannot be tested with con-
ventional automotive electrical test equipment. If the
hazard switch module is believed to be faulty, replace
the switch with a known good unit to confirm system
operation.
Fig. 21 Hazard Switch
1 - HAZARD SWITCH BUTTON
2 - SCREW (1)
3 - MOUNTING BRACKET TABS
KJLAMPS/LIGHTING - EXTERIOR 8L - 29

(5) Pinch the two hooked ends of the wire head-
lamp bulb retainer clip together and disengage them
from the slots in the flange of the reflector (Fig. 26).
(6) Pivot the headlamp bulb retainer clip up off of
the bulb flange and out of the way.
CAUTION: Do not contaminate the bulb glass by
touching it with your fingers or by allowing it to
contact other oily surfaces. Shortened bulb life will
result.
(7) Pull the bulb straight out of the headlamp unit
reflector (Fig. 27).
INSTALLATION
NORTH AMERICA
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.
CAUTION: Do not contaminate the bulb glass by
touching it with your fingers or by allowing it to
contact other oily surfaces. Shortened bulb life will
result.
(1) Position the headlamp bulb and socket unit
into the lock ring (Fig. 24).(2) Reconnect the grille opening reinforcement
wire harness connector for the headlamp bulb to the
connector receptacle on the bulb socket.
(3) Position the lock ring, socket, and bulb down
behind the upper radiator crossmember and align
them with the socket opening on the back of the
headlamp unit housing.
(4) Push the socket and bulb straight into the
headlamp unit housing until they are firmly seated.
(5) Position the lock ring over the socket and
engage it with the flange on the back of the head-
lamp unit housing (Fig. 23).
(6) Rotate the lock ring on the back of the head-
lamp unit housing clockwise about 30 degrees.
(7) Reconnect the battery negative cable.
REST-OF-WORLD
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.
CAUTION: Do not contaminate the bulb glass by
touching it with your fingers or by allowing it to
contact other oily surfaces. Shortened bulb life will
result.
(1) Position the bulb into the headlamp unit reflec-
tor (Fig. 27).
(2) Pivot the headlamp bulb retainer clip back over
the bulb flange.
Fig. 26 Headlamp Bulb Retainer Clip Engage/
Disengage
1 - RETAINER CLIP
2 - BULB BASE
3 - HEADLAMP HOUSING
4 - REFLECTOR
5 - BULB FLANGE
6 - RETAINER SLOTS
Fig. 27 Headlamp Bulb Remove/Install
1 - BULB BASE
2 - RETAINER CLIP
3 - LEVELING MOTOR (IF EQUIPPED)
4 - REFLECTOR
5 - HEADLAMP HOUSING
6 - BULB FLANGE
8L - 32 LAMPS/LIGHTING - EXTERIORKJ
HEADLAMP BULB (Continued)

(7) Pull the bulb straight out of the license plate
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.
NORTH AMERICA
(1) Align the base of the bulb with the receptacle
in the license plate lamp unit socket.
(2) Push the bulb straight into the license plate
lamp unit socket until it is firmly seated.
(3) Reach through the opening in the rear bumper
fascia between the license plate and the lamp to
align the socket and bulb with the socket opening on
the back of the lamp unit housing (Fig. 45).
(4) Push the socket and bulb straight into the
license plate lamp unit housing until it is firmly
seated.
(5) Reconnect the battery negative cable.
REST-OF-WORLD
(1) Align the base of the bulb with the receptacle
in the license plate lamp unit socket.
(2) Push the bulb straight into the license plate
lamp unit socket until it is firmly seated.
(3) Align the socket and bulb with the socket open-
ing on the top of the license plate lamp unit housing
(Fig. 47).(4) Push the socket and bulb straight into the
license plate lamp unit housing until it is firmly
seated.
(5) Rotate the socket on the top of the license plate
lamp unit housing clockwise about 30 degrees.
(6) Swing the license plate bracket back against
the spare tire (Fig. 46).
(7) Lift up the bottom of the license mounting
plate far enough to install and tighten the two
screws that secure the license plate bracket to the
special lug nuts on the spare tire. Tighten the screws
to 28 N´m (21 ft. lbs.).
(8) Lower the bottom of the license mounting plate
and, using hand pressure, snap it into place on the
license plate bracket.
(9) Reconnect the battery negative cable.
LICENSE PLATE LAMP UNIT
REMOVAL
NORTH AMERICA
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the two screws that secure the license
plate lamp unit to the rear bumper fascia (Fig. 48).
(3) Pull the license plate lamp unit down and out
through the mounting hole in the rear bumper fascia
far enough to access and disconnect the wire harness
connector for the lamp socket pigtail wire.
(4) Remove the license plate lamp unit from the
rear bumper fascia.
Fig. 47 License Plate Lamp Bulb Remove/Install -
Rest-Of-World
1 - LAMP UNIT (2)
2 - LICENSE PLATE BRACKET
3 - SCREW (4)
4 - BULB & SOCKET (2)
Fig. 48 License Plate Lamp Unit Remove/Install
1 - REAR BUMPER FASCIA
2 - LICENSE PLATE LAMP UNIT
3 - SCREW (2)
KJLAMPS/LIGHTING - EXTERIOR 8L - 45
LICENSE PLATE LAMP BULB (Continued)

Be certain any removed bulb is replaced with the
same bulb size and type that was removed.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the rear lamp unit from the end of the
quarter panel. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/REAR LAMP UNIT -
REMOVAL).
(3) Firmly grasp the socket on the socket plate at
the back of the rear lamp unit housing for the bulb
that is being removed (Fig. 59).
(4) Rotate the socket on the socket plate at the
back of the rear lamp unit housing counterclockwise
about 30 degrees.
(5) Pull the socket and bulb straight out of the
back of the rear lamp unit housing.
(6) Pull the bulb straight out of the rear 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 rear lamp unit socket.
(2) Push the bulb straight into the rear lamp unit
socket until it is firmly seated.
(3) Align the socket and bulb with the opening in
the socket plate on the back of the rear lamp unit
housing (Fig. 59).(4) Push the socket and bulb straight into the rear
lamp unit housing until the socket is firmly seated
against the socket plate.
(5) Rotate the socket on the socket plate at the
back of the rear lamp unit housing clockwise about
30 degrees.
(6) Reinstall the rear lamp unit onto the end of the
quarter panel. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/REAR LAMP UNIT -
INSTALLATION).
(7) Reconnect the battery negative cable.
REAR LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Open the tailgate to access and remove the two
screws that secure the inboard side of the rear lamp
unit to the side jamb of the tailgate opening (Fig. 60).
(3) Pull the outboard side of the rear lamp unit
rearward (away from the end of the quarter panel)
far enough to unsnap the two ball studs on the out-
board side of the lamp housing from the plastic nuts
in the quarter panel.
(4) Pull the rear lamp unit away from the quarter
panel far enough to access and disconnect the wire
harness connector for the lamp unit from the connec-
tor receptacle on the lamp socket plate.
(5) Remove the rear lamp unit from the quarter
panel.
Fig. 59 Rear Lamp Bulb Remove/Install
1 - REAR LAMP HOUSING
2 - BULB HOLDER
3 - BULB
4 - SOCKET PLATE
Fig. 60 Rear Lamp Unit Remove/Install
1 - PLASTIC NUT (2)
2 - WIRE HARNESS CONNECTOR
3 - PLASTIC NUT (2)
4 - REAR LAMP UNIT
5 - SCREW (2)
KJLAMPS/LIGHTING - EXTERIOR 8L - 59
REAR LAMP BULB (Continued)

(6) Remove the plastic nuts from the quarter panel
and discard.
INSTALLATION
(1) Install new plastic nuts into the quarter panel
(Fig. 60).
(2) Position the rear lamp unit to the quarter
panel.
(3) Reconnect the wire harness connector for the
rear lamp unit to the connector receptacle on the
lamp socket plate.
(4) Align the two ball studs on the outboard side of
the rear lamp unit housing with the plastic nuts in
the quarter panel.
(5) Using hand pressure, push the outboard side of
the rear lamp unit forward (towards the end of the
quarter panel) far enough to snap the two ball studs
on the outboard side of the lamp housing into the
plastic nuts in the quarter panel.
(6) Align the mounting holes on the inboard side of
the rear lamp unit housing with the plastic nuts in
the side jamb of the tailgate opening.
(7) Install and tighten the two screws that secure
the inboard side of the rear lamp unit housing to the
plastic nuts in the side jamb of the tailgate opening.
Tighten the screws to 2 N´m (20 in. lbs.).
(8) Reconnect the battery negative cable.
REPEATER LAMP BULB
REMOVAL
Side repeater lamps are used only on vehicles man-
ufactured for certain markets where these lamps are
required.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the repeater lamp unit from the front
fender panel. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/REPEATER LAMP UNIT -
REMOVAL).
(3) Rotate the repeater lamp socket in the lamp
lens counterclockwise about 30 degrees (Fig. 61).
(4) Pull the socket and bulb straight out of the
repeater lamp lens.
(5) Pull the bulb straight out of the repeater lamp
socket.
INSTALLATION
Side repeater lamps are used only on vehicles man-
ufactured for certain markets where these lamps are
required.
CAUTION: Always use the correct bulb size and
type for replacement. An incorrect bulb size or typemay 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 repeater lamp socket.
(2) Push the bulb straight into the repeater lamp
socket until it is firmly seated.
(3) Align the socket and bulb with the socket open-
ing in the repeater lamp lens (Fig. 61).
(4) Push the socket and bulb straight into the
repeater lamp lens until it is firmly seated
(5) Rotate the repeater lamp socket in the lamp
lens clockwise about 30 degrees.
(6) Reinstall the repeater lamp unit onto the front
fender panel. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/REPEATER LAMP UNIT -
INSTALLATION).
(7) Reconnect the battery negative cable.
REPEATER LAMP UNIT
REMOVAL
Side repeater lamps are used only on vehicles man-
ufactured for certain markets where these lamps are
required.
(1) Disconnect and isolate the battery negative
cable.
(2) Using a trim stick or another suitable wide
flat-bladed tool, carefully pry at the clearance notch
in the lower edge of the repeater lamp lens to disen-
gage the snap features of the lens from the mounting
hole in the front fender panel (Fig. 62).
(3) Pull the repeater lamp unit out from the front
fender panel far enough to access and disconnect the
Fig. 61 Repeater Lamp Bulb Remove/Install
1 - FRONT FENDER
2 - SOCKET
3 - BULB
4 - LENS
8L - 60 LAMPS/LIGHTING - EXTERIORKJ
REAR LAMP UNIT (Continued)

LAMPS/LIGHTING - INTERIOR
TABLE OF CONTENTS
page page
LAMPS/LIGHTING - INTERIOR
DESCRIPTION.........................65
OPERATION...........................67
DIAGNOSIS AND TESTING - LAMPS/
LIGHTING - INTERIOR..................68
SPECIFICATIONS - LAMPS/LIGHTING -
INTERIOR...........................71
ASH RECEIVER LAMP BULB
REMOVAL.............................71
INSTALLATION.........................71
ASH RECEIVER LAMP UNIT
REMOVAL.............................72
INSTALLATION.........................72
CARGO LAMP BULB
REMOVAL.............................72
INSTALLATION.........................73
CARGO LAMP SWITCH
REMOVAL.............................73
INSTALLATION.........................74
CARGO LAMP UNIT
REMOVAL.............................74
INSTALLATION.........................74
COMPASS MINI-TRIP ILLUMINATION BULB
REMOVAL.............................74
INSTALLATION.........................75
COURTESY LAMP BULB
REMOVAL.............................75
INSTALLATION.........................76
COURTESY LAMP UNIT
REMOVAL.............................76INSTALLATION.........................77
DOOR AJAR SWITCH
DESCRIPTION.........................77
OPERATION...........................77
FLIP-UP GLASS AJAR SWITCH
DESCRIPTION.........................77
OPERATION...........................77
HEATER-A/C CONTROL ILLUMINATION BULB
REMOVAL.............................78
INSTALLATION.........................78
READING LAMP BULB
REMOVAL.............................79
INSTALLATION.........................79
READING LAMP SWITCH
REMOVAL.............................80
INSTALLATION.........................80
READING LAMP UNIT
REMOVAL.............................81
INSTALLATION.........................81
TAILGATE AJAR SWITCH
DESCRIPTION.........................82
OPERATION...........................82
TRANSMISSION RANGE INDICATOR
ILLUMINATION BULB
REMOVAL.............................82
INSTALLATION.........................83
VANITY LAMP BULB
REMOVAL.............................83
INSTALLATION.........................84
LAMPS/LIGHTING - INTERIOR
DESCRIPTION
The interior lighting system (Fig. 1) for this model
includes the following incandescent interior lamps:
²Ash Receiver Lamp- An available ash receiver
lamp is located above the ash receiver housing
behind the instrument panel center bezel, and is con-
trolled by the panel lamps dimmer circuit.
²Cargo Lamp- An available cargo lamp with an
integral lens-actuated courtesy disable switch is
located in the headliner near the rear roof header,
and is controlled by the courtesy lamp circuit.
²Courtesy Lamps- Available courtesy lamps are
located below both the right and left side of the
instrument panel, and are controlled by the courtesy
lamp circuit.²Compass Mini-Trip Control Illumination
Lamps- The optional Compass Mini-Trip Computer
(CMTC) has three replaceable control illumination
bulb/bulb holder units on its circuit board that are
controlled by the panel lamps dimmer circuit.
²Dome Lamp- A standard front dome lamp that
does not include an on-off switch is located in the
headliner near the windshield header, and is con-
trolled by the courtesy lamp circuit.
²Hazard Switch Illumination/Indicator
Lamp- The hazard switch control button has a non-
replaceable illumination/indicator bulb soldered onto
its circuit board that is controlled by both the hazard
switch circuitry and the panel lamps dimmer circuit.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/HAZARD SWITCH - DESCRIPTION).
²Heater-Air Conditioner Control Illumina-
tion Lamps- The heater-air conditioner control has
KJLAMPS/LIGHTING - INTERIOR 8L - 65

mission have an illuminated transmission range indi-
cator integral to the console mounted gearshift
mechanism, and controlled by the panel lamps dim-
mer circuit.
²Vanity Lamps- Available single intensity van-
ity lamps are located on each side of a covered mirror
on both the right and left sun visors, and are con-
trolled by an integral vanity mirror cover-actuated
switch on the courtesy lamp circuit.
Other components of the interior lighting system
for this model include:
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).
²Door Ajar Switches- A door ajar switch is
integral to the door latch mechanism of each front
and rear door.
²Flip-Up Glass Ajar Switch- A flip-up glass
ajar switch is integral to the flip-up glass latch mech-
anism on the top of the tailgate inner panel.
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. (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING
- EXTERIOR/MULTI-FUNCTION SWITCH -
DESCRIPTION).
²Tailgate Ajar Switch- A tailgate ajar switch is
integral to the latch mechanism of the tailgate.
Hard wired circuitry connects the interior 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 interior 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
The interior lighting systems can be divided into
two general classifications based upon the circuit
that controls their operation: The courtesy lamp cir-cuit, or the panel lamps dimmer circuit. Following
are paragraphs that briefly describe the operation of
each of the major interior lighting systems. The hard
wired circuits and components of the interior lighting
systems may be diagnosed and tested using conven-
tional diagnostic tools and procedures. However, con-
ventional diagnostic methods may not prove
conclusive in the diagnosis of the Body Control Mod-
ule (BCM), the ElectroMechanical Instrument Clus-
ter (EMIC), or the Programmable Communications
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 sys-
tems requires the use of a DRBIIItscan tool. Refer
to the appropriate diagnostic information.
COURTESY LAMP CIRCUIT Depending upon the
selected vehicle options the courtesy lamp circuit
may include the courtesy lamps located below the
instrument panel, the dome or map/reading lamps
located in the headliner near the windshield, the
cargo lamp located in the headliner near the rear
roof header, and the vanity lamps located in the sun
visors. The lamps in the courtesy lamp circuit are
provided with battery current at all times from a
fused B(+) fuse in the Junction Block (JB) through a
fused B(+) circuit. The Body Control Module (BCM)
controls the ground path for these lamps using an
internal driver through the courtesy lamp driver cir-
cuit based upon hard wired inputs from the door ajar
switches, the flip-up glass ajar switch, and the tail-
gate ajar switch. After all of the ajar switch inputs to
the BCM transition to open, the BCM will keep the
lamps illuminated for about 27 seconds, then fade
the lamps to off (theater dimming) over about three
seconds.
The BCM also provides courtesy lamp operation
based upon a resistor multiplexed input from the
interior lighting control ring on the left (lighting)
control stalk of the multi-function switch through the
headlamp switch mux circuit, and in response to cer-
tain inputs from the optional Remote Keyless Entry
(RKE) system. A resistor multiplexed courtesy lamp
defeat input from the control ring on the left (light-
ing) control stalk of the multi-function switch will
cause the BCM to override normal courtesy lamp
operation based upon inputs from all of the ajar
switches. A hard wired input from the courtesy lamp
defeat switch in the optional cargo lamp through a
rear courtesy lamp control circuit will cause the BCM
to override normal courtesy lamp operation based
upon inputs from only the flip-up glass and tailgate
ajar switches.
For those lamps on the courtesy lamp circuit with
independent switching, such as the optional reading
lamps and vanity lamps, the BCM provides a ground
KJLAMPS/LIGHTING - INTERIOR 8L - 67
LAMPS/LIGHTING - INTERIOR (Continued)

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)