service JEEP LIBERTY 2002 KJ / 1.G Owners Manual

(2) Remove the heated seat switch (Refer to 8 -
ELECTRICAL/HEATED SEATS/DRIVER HEATED
SEAT SWITCH - REMOVAL). Check for continuity
between the ground circuit cavity #5 of the heated
seat switch connector and a good ground. There
should be continuity. If OK, go to Step 3. If not OK,
repair the open ground circuit as required.
(3) Turn the ignition switch to the ON position.
Check for battery voltage at the fused ignition switch
output circuit cavity #1 of the heated seat switch con-
nector. If OK, go to Step 4. If not OK, repair the open
fused ignition switch output circuit as required.
(4) Check the continuity between pin #1 and pin
#3 of the heated seat switch (Fig. 4). If the readings
do not correspond to those in the Heated Seat Switch
Continuity table below, replace the heated seat
switch. If OK, and the heated seat system is still not
operating properly refer toDiagnosis and Testing
the Heated Seat Module.NOTE: ANY RESISTANCE VALUES (OHMSV) GIVEN
IN THE FOLLOWING TEXT ARE SUPPLIED USING
THE AUTOMATIC RANGE GENERATED BY A
FLUKETAUTOMOTIVE METER. IF ANOTHER TYPE
OF MEASURING DEVICE IS USED, THE VALUES
GENERATED MAY NOT BE THE SAME AS THE
RESULTS SHOWN HERE, OR MAY HAVE TO BE
CONVERTED TO THE RANGE USED HERE.
HEATED SEAT SWITCH CONTINUITY
CONTINUITY
BETWEENSWITCH
POSITIONOHMS
READING +/±
10%
PIN 1 AND 3 OFF 2.2 K (2200)
OHMS
PIN 1 AND 3 LO .415 K (415)
OHMS
PIN 1 AND 3 HI 33 OHMS
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the appropriate seat cushion side
shield (Refer to 23 - BODY/SEATS/SEAT CUSHION
SIDE COVERS - REMOVAL).
(3) Disconnect the heated seat switch electrical
connector. Depress the locking tab and pull straight
apart.
(4) Working from the underside of the switch, gen-
tly rock the switch back and forth out of its mounting
location.
INSTALLATION
(1) Gently rock the switch back and forth in to its
mounting location.
(2) Connect the heated seat switch electrical con-
nector.
(3) Install the appropriate seat cushion side shield.
Refer to the Body section of the service manual for
the procedure.
(4) Connect the negative battery cable.
Fig. 4 Heated Seat Switches
KJHEATED SEAT SYSTEM 8G - 15
PASSENGER SEAT HEATER SWITCH (Continued)

HORN
TABLE OF CONTENTS
page page
HORN SYSTEM
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING - HORN SYSTEM . . . 1
HORN
DIAGNOSIS AND TESTING - HORN..........2
REMOVAL.............................3
INSTALLATION..........................3HORN RELAY
DIAGNOSIS AND TESTING - HORN RELAY....3
REMOVAL.............................3
INSTALLATION..........................3
HORN SWITCH
DESCRIPTION..........................4
DIAGNOSIS AND TESTING - HORN SWITCH . . . 4
HORN SYSTEM
DESCRIPTION
A dual-note electric horn system is standard facto-
ry-installed equipment on this model (Fig. 1).
The dual-note horn system features dual electro-
magnetic horn units. The horn system includes the
following major components:
²Horn- The two horns are located below the
Power Distribution Center (PDC).
²Horn Relay- The horn relay is located in the
Junction Block (JB).²Horn Switch- The horn switch is molded into
the driver airbag assembly.OPERATION
The horn system operates on battery current
received through fuse 3 in the Junction Block (JB).
The horn system circuit is designed so that the sys-
tem will remain operational, regardless of the igni-
tion switch position.
DIAGNOSIS AND TESTING - HORN SYSTEM
In most cases, any problem involving continually
sounding horns can be quickly alleviated by removing
the horn relay from the Junction Block (JB). Refer to
horn relay for the removal procedure. Refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
Fig. 1 HORN LOCATION
1 - HIGH NOTE HORN
2 - LOW NOTE HORN
KJHORN 8H - 1

HORN SYSTEM DIAGNOSIS TABLE
CONDITION POSSIBLE CAUSES CORRECTION
BOTH HORNS
INOPERATIVE1. Faulty fuse. 1. Check the fuse in the Junction Block (JB).
Replace the fuse and repair the shorted circuit or
component, if required.
2. Faulty horn relay. 2. Refer to horn relay for the proper diagnosis
and testing procedures. Replace the horn relay or
repair the open horn relay circuit, if required.
3. Faulty horn switch. 3. Refer to horn switch for the proper diagnosis
and testing procedure. Replace the horn switch or
repair the open horn switch circuit, if required.
4. Faulty horns. 4. Refer to horn for the proper diagnosis and
testing procedure. Replace the horns or repair the
open horn circuit, if required.
ONE HORN INOPERATIVE 1. Faulty horn. 1. Refer to horn for the proper diagnosis and
testing procedures. Replace the horn or repair the
open horn circuit, if required.
HORN SOUNDS
CONTINUOUSLY1. Faulty horn relay. 1. Refer to horn relay for the proper diagnosis
and testing procedure. Replace the horn relay or
repair the shorted horn relay control circuit, if
required.
2. Faulty horn switch. 2. Refer to horn switch for the proper diagnosis
and testing procedure. Replace the horn switch or
repair the shorted horn switch circuit, if required.
HORN
DIAGNOSIS AND TESTING - HORN
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, further details
on wire harness routing and retention, as well as
pin-out and location views for the various wire har-
ness connectors, splices and grounds.(1) Disconnect the wire harness connector from the
horn. Measure the resistance between the horn
ground circuit cavity of the wire harness connector
and a good ground. There should be no measurable
resistance. If OK, go to Step 2. If not OK, replace
wiring as necessary.
(2) Check for battery voltage at the horn relay out-
put circuit cavity of the wire harness connector for
the horn. There should be zero volts. If OK, go to
Step 3. If not OK, refer to horn relay and horn relay
circuit for the proper diagnosis and testing proce-
dures.
(3) Depress the horn switch. There should now be
battery voltage at the horn relay output circuit cavity
of the wire harness connector for the horn. If OK, but
the horn does not sound, replace the faulty horn. If
not OK, refer to horn relay and horn relay circuit for
the proper diagnosis and testing procedures.
8H - 2 HORNKJ
HORN SYSTEM (Continued)

HORN SWITCH
DESCRIPTION
The horn switch is molded into the driver airbag
assembly. The horn switch can not be serviced sepa-
rately. For service procedures, (Refer to 8 - ELEC-
TRICAL/RESTRAINTS/DRIVER AIRBAG -
REMOVAL).
DIAGNOSIS AND TESTING - HORN SWITCH
For complete circuit diagrams, refer to the appro-
priate 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: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the steering column opening cover.
(3) Check for continuity between the metal steer-
ing column jacket and a good ground. There should
be continuity. If OK, go to Step 4. If not OK,(Refer to
19 - STEERING/COLUMN - INSTALLATION) for
proper installation of the steering column.
(4) Remove the driver side airbag module from the
steering wheel (Refer to 8 - ELECTRICAL/RE-
STRAINTS/DRIVER AIRBAG - REMOVAL). Discon-
nect the horn switch wire harness connectors from
the driver side airbag module (Fig. 4).
(5) Remove the horn relay from the Junction Block
(JB). Check for continuity between the steering col-umn half of the horn switch feed wire harness con-
nector and a good ground. There should be no
continuity. If OK, go to Step 6. If not OK, repair the
shorted horn relay control circuit to the horn relay in
the Junction Block as required.
(6) Check for continuity between the steering col-
umn half of the horn switch feed wire harness con-
nector and the horn relay control circuit cavity for
the horn relay in the Junction Block. There should be
continuity. If OK, go to Step 7. If not OK, repair the
open horn relay control circuit to the horn relay in
the Junction Block as required.
(7) Check for continuity between the horn switch
feed wire and the horn switch ground wire on the
driver side airbag module. There should be no conti-
nuity. If OK, go to Step 8. If not OK, replace the
faulty horn switch.
(8) Depress the center of the driver side airbag
module trim cover and check for continuity between
the horn switch feed wire and the horn switch
ground wire on the driver side airbag module. There
should now be continuity. If not OK, replace the
faulty horn switch (Refer to 8 - ELECTRICAL/RE-
STRAINTS/DRIVER AIRBAG - REMOVAL).
Fig. 4 Driver Airbag Housing
1 - HOUSING
2 - HORN SWITCH GROUND WIRE
3 - HORN SWITCH FEED WIRE
4 - INFLATOR
5 - TRIM COVER
8H - 4 HORNKJ

cylinders 1 and 4, and coil number two fires cylinders
2 and 3.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil(s). The
PCM will de-energize the ASD relay if it does not
receive the crankshaft position sensor and camshaft
position sensor inputs.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Spark plug cables (secondary wires or cables) are
used with the 2.4L engine.
3.7L
Battery voltage is supplied to the 6 ignition coils
from the ASD relay. The Powertrain Control Module
(PCM) opens and closes each ignition coil ground cir-
cuit at a determined time for ignition coil operation.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used with the 3.7L engine.
REMOVAL
2.4L
(1) Disconnect electrical connector at rear of coil.
(2) Remove all secondary cables from coil.
(3) Remove 4 coil mounting bolts (Fig. 17).
(4) Remove coil from vehicle.
3.7L
An individual ignition coil is used for each spark
plug (Fig. 19). The coil fits into machined holes in the
cylinder head. A mounting stud/nut secures each coil
to the top of the intake manifold (Fig. 18). The bot-
tom of the coil is equipped with a rubber boot to seal
the spark plug to the coil. Inside each rubber boot is
a spring. The spring is used for a mechanical contact
between the coil and the top of the spark plug. These
rubber boots and springs are a permanent part of the
coil and are not serviced separately. An o-ring (Fig.19) is used to seal the coil at the opening into the cyl-
inder head.
(1) Depending on which coil is being removed, the
throttle body air intake tube or intake box may need
to be removed to gain access to coil.
(2) Disconnect electrical connector from coil by
pushing downward on release lock on top of connec-
tor and pull connector from coil.
(3) Clean area at base of coil with compressed air
before removal.
(4) Remove coil mounting nut from mounting stud
(Fig. 18).
(5) Carefully pull up coil from cylinder head open-
ing with a slight twisting action.
(6) Remove coil from vehicle.
INSTALLATION
2.4L
(1) Position coil to engine.
(2) Install 4 mounting bolts. Refer to torque speci-
fications.
(3) Install secondary cables.
(4) Install electrical connector at rear of coil.
(5) Install air cleaner tube and housing.
3.7L
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Check condition of coil o-ring and replace as
necessary. To aid in coil installation, apply silicone to
coil o-ring.
Fig. 17 IGNITION COIL - 2.4L
1 - IGNITION COIL
2 - MOUNTING BOLTS (4)
8I - 10 IGNITION CONTROLKJ
IGNITION COIL (Continued)

TURN SIGNAL INDICATOR
DESCRIPTION.........................34
OPERATION...........................34
WAIT-TO-START INDICATOR
DESCRIPTION.........................35
OPERATION...........................35
WASHER FLUID INDICATOR
DESCRIPTION.........................35OPERATION...........................36
DIAGNOSIS AND TESTING - WASHER FLUID
INDICATOR..........................36
WATER-IN-FUEL INDICATOR
DESCRIPTION.........................37
OPERATION...........................37
INSTRUMENT CLUSTER
DESCRIPTION
The instrument cluster for this model is an Elec-
troMechanical Instrument Cluster (EMIC) module
that is located in the instrument panel above the
steering column opening, directly in front of the
driver (Fig. 1). The remainder of the EMIC, including
the mounts and the electrical connections, are con-
cealed behind the cluster bezel. The EMIC gauges
and indicators are protected by an integral clear
plastic cluster lens, and are visible through a dedi-
cated opening in the cluster bezel on the instrument
panel. Just behind the cluster lens is the cluster hood
and an integral cluster mask, which are constructed
of molded black plastic. Two cluster masks are used;
a base black version is used on base models, while a
premium black version features a chrome trim ring
around the perimeter of each gauge opening is used
on premium models. The cluster hood serves as a
visor and shields the face of the cluster from ambient
light and reflections to reduce glare, while the cluster
mask serves to separate and define the individual
gauges and indicators of the EMIC. On the lower
edge of the cluster lens just right of the speedometer,
the black plastic odometer/trip odometer switch but-
ton protrudes through dedicated holes in the clustermask and the cluster lens. The molded plastic EMIC
lens, hood and mask unit has three integral mount-
ing tabs, one each on the lower outboard corners of
the unit and one on the upper surface of the hood
near the center. These mounting tabs are used to
secure the EMIC to the molded plastic instrument
panel cluster carrier with two screws at the top, and
one screw at each outboard tab. A single molded con-
nector receptacle located on the EMIC electronic cir-
cuit board is accessed from the back of the cluster
housing and is connected to the vehicle electrical sys-
tem through a single dedicated take out and connec-
tor of the instrument panel wire harness.
Behind the cluster lens, hood, and mask unit is the
cluster overlay and gauges. The overlay is a lami-
nated plastic unit. The dark, visible, outer surface of
the overlay is marked with all of the gauge dial faces
and graduations, but this layer is also translucent.
The darkness of this outer layer prevents the cluster
from appearing cluttered or busy by concealing the
cluster indicators that are not illuminated, while the
translucence of this layer allows those indicators and
icons that are illuminated to be readily visible. The
underlying layer of the overlay is opaque and allows
light from the various indicators and illumination
lamps behind it to be visible through the outer layer
of the overlay only through predetermined cutouts.
The orange gauge pointers are each illuminated
internally. The EMIC electronic circuitry is protected
by a molded plastic rear cover that features several
round access holes for service of the cluster illumina-
tion lighting and a single rectangular access hole for
the EMIC connector receptacle. The EMIC housing,
circuit board, gauges, and overlay unit are sand-
wiched between the lens, hood, and mask unit and
the rear cover with screws.
Twelve versions of the EMIC module are offered on
this model, six base and six premium. These versions
accommodate all of the variations of optional equip-
ment and regulatory requirements for the various
markets in which the vehicle will be offered. This
module utilizes integrated circuitry and information
carried on the Programmable Communications Inter-
face (PCI) data bus network for control of all gauges
and many of the indicators. (Refer to 8 - ELECTRI-
CAL/ELECTRONIC CONTROL MODULES/COM-
MUNICATION - DESCRIPTION - PCI BUS). The
EMIC also uses several hard wired inputs in order to
Fig. 1 Instrument Cluster
1 - INSTRUMENT PANEL
2 - INSTRUMENT CLUSTER
8J - 2 INSTRUMENT CLUSTERKJ

perform its many functions. The EMIC module incor-
porates a blue-green digital Vacuum Fluorescent Dis-
play (VFD) for displaying odometer and trip
odometer information, as well as several warning
messages and certain diagnostic information. In addi-
tion to instrumentation and indicators, the EMIC has
the hardware and software needed to provide the fol-
lowing features:
²Chime Warning Service- A chime tone gener-
ator on the EMIC electronic circuit board provides
audible alerts to the vehicle operator and eliminates
the need for a separate chime module. (Refer to 8 -
ELECTRICAL/CHIME WARNING SYSTEM -
DESCRIPTION).
²Panel Lamps Dimming Service- The EMIC
provides a hard wired 12-volt Pulse-Width Modulated
(PWM) output that synchronizes the dimming level
of the radio display, gear selector indicator, heater-air
conditioner control, and all other dimmable lighting
on the panel lamps dimmer circuit with that of the
cluster illumination lamps and VFD.
The EMIC houses four analog gauges and has pro-
visions for up to twenty-four indicators (Fig. 2). The
EMIC includes the following analog gauges:
²Coolant Temperature Gauge
²Fuel Gauge
²Speedometer
²Tachometer
Some of the EMIC indicators are automatically
configured when the EMIC is connected to the vehi-
cle electrical system for compatibility with certain
optional equipment or equipment required for regula-
tory purposes in certain markets. While each EMIC
may have provisions for indicators to support every
available option, the configurable indicators will not
be functional in a vehicle that does not have the
equipment that an indicator supports. The EMIC
includes provisions for the following indicators (Fig.
2):
²Airbag Indicator (with Airbag System only)
²Antilock Brake System (ABS) Indicator
(with ABS only)
²Brake Indicator
²Charging Indicator
²Coolant Low Indicator (with Diesel Engine
only)
²Cruise Indicator (with Speed Control Sys-
tem only)
²Four-Wheel Drive Full Time Indicator (with
Selec-Trac Transfer Case only)
²Four-Wheel Drive Low Mode Indicator
²Four-Wheel Drive Part Time Indicator
²Front Fog Lamp Indicator (with Front Fog
Lamps only)
²High Beam Indicator
²Low Fuel Indicator²Low Oil Pressure Indicator
²Malfunction Indicator Lamp (MIL)
²Overdrive-Off Indicator (with Automatic
Transmission only)
²Rear Fog Lamp Indicator (with Rear Fog
Lamps only)
²Seatbelt Indicator
²Security Indicator (with Vehicle Theft
Security System only)
²Sentry Key Immobilizer System (SKIS)
Indicator (with SKIS only)
²Transmission Overtemp Indicator (with
Automatic Transmission only)
²Turn Signal (Right and Left) Indicators
²Wait-To-Start Indicator (with Diesel Engine
only)
²Water-In-Fuel Indicator (with Diesel Engine
only)
Each indicator in the EMIC is illuminated by a
dedicated Light Emitting Diode (LED) that is sol-
dered onto the EMIC electronic circuit board. The
LEDs are not available for service replacement and,
if damaged or faulty, the entire EMIC must be
replaced. Cluster illumination is accomplished by
dimmable incandescent back lighting, which illumi-
nates the gauges for visibility when the exterior
lighting is turned on. Each of the incandescent bulbs
is secured by an integral bulb holder to the electronic
circuit board from the back of the cluster housing.
The incandescent bulb/bulb holder units are available
for service replacement.
Hard wired circuitry connects the EMIC to the
electrical system of the vehicle. These hard wired cir-
cuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system
and to the EMIC 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.
The EMIC modules for this model are serviced only
as complete units. The EMIC module cannot be
adjusted or repaired. If a gauge, an LED indicator,
the VFD, the electronic circuit board, the circuit
board hardware, the cluster overlay, or the EMIC
housing are damaged or faulty, the entire EMIC mod-
ule must be replaced. The cluster lens, hood and
mask unit and the individual incandescent lamp
bulbs with holders are available for service replace-
ment.
KJINSTRUMENT CLUSTER 8J - 3
INSTRUMENT CLUSTER (Continued)

OPERATION
The ElectroMechanical Instrument Cluster (EMIC)
is designed to allow the vehicle operator to monitor
the conditions of many of the vehicle components and
operating systems. The gauges and indicators in the
EMIC provide valuable information about the various
standard and optional powertrains, fuel and emis-
sions systems, cooling systems, lighting systems,
safety systems and many other convenience items.
The EMIC is installed in the instrument panel so
that all of these monitors can be easily viewed by the
vehicle operator when driving, while still allowing
relative ease of access for service. The microproces-sor-based EMIC hardware and software uses various
inputs to control the gauges and indicators visible on
the face of the cluster. Some of these inputs are hard
wired, but most are in the form of electronic mes-
sages that are transmitted by other electronic mod-
ules over the Programmable Communications
Interface (PCI) data bus network. (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/COMMUNICATION - OPERATION).
The EMIC microprocessor smooths the input data
using algorithms to provide gauge readings that are
accurate, stable and responsive to operating condi-
tions. These algorithms are designed to provide
Fig. 2 EMIC Gauges & Indicators
1 - SKIS INDICATOR 16 - REAR FOG LAMP INDICATOR
2 - AIRBAG INDICATOR 17 - ABS INDICATOR
3 - LOW FUEL INDICATOR 18 - CHARGING INDICATOR
4 - WAIT-TO-START INDICATOR 19 - WATER-IN-FUEL INDICATOR
5 - OVERDRIVE-OFF INDICATOR 20 - ENGINE TEMPERATURE GAUGE
6 - COOLANT LOW INDICATOR 21 - ODOMETER/TRIP ODOMETER SWITCH BUTTON
7 - SEATBELT INDICATOR 22 - ODOMETER/TRIP ODOMETER DISPLAY
8 - TACHOMETER 23 - CRUISE INDICATOR
9 - LEFT TURN INDICATOR 24 - LOW OIL PRESSURE INDICATOR
10 - HIGH BEAM INDICATOR 25 - TRANSMISSION OVERTEMP INDICATOR
11 - RIGHT TURN INDICATOR 26 - PART TIME 4WD INDICATOR
12 - SPEEDOMETER 27 - BRAKE INDICATOR
13 - FRONT FOG LAMP INDICATOR 28 - FULL TIME 4WD INDICATOR
14 - 4WD LOW MODE INDICATOR 29 - SECURITY INDICATOR
15 - MALFUNCTION INDICATOR LAMP (MIL) 30 - FUEL GAUGE
8J - 4 INSTRUMENT CLUSTERKJ
INSTRUMENT CLUSTER (Continued)

gauge readings during normal operation that are con-
sistent with customer expectations. However, when
abnormal conditions exist such as high coolant tem-
perature, the algorithm can drive the gauge pointer
to an extreme position and the microprocessor can
sound a chime through the on-board chime tone gen-
erator to provide distinct visual and audible indica-
tions of a problem to the vehicle operator. The
instrument cluster circuitry may also perform chime
service for other electronic modules in the vehicle
based upon electronic chime tone request messages
received over the PCI data bus to provide the vehicle
operator with an audible alert to supplement a visual
indication. One such alert is a door ajar warning
chime, which the EMIC provides by monitoring PCI
bus messages from the Body Control Module (BCM).
The EMIC circuitry operates on battery current
received through a fused B(+) fuse in the Junction
Block (JB) on a non-switched fused B(+) circuit, and
on battery current received through a fused ignition
switch output (run-start) fuse in the JB on a fused
ignition switch output (run-start) circuit. This
arrangement allows the EMIC to provide some fea-
tures regardless of the ignition switch position, while
other features will operate only with the ignition
switch in the On or Start positions. The EMIC
receives a ground input from the BCM as a wake-up
signal in order to provide the ignition-off features.
The EMIC circuitry is grounded through a ground
circuit and take out of the instrument panel wire
harness with an eyelet terminal connector that is
secured by a nut to a ground stud located on the left
instrument panel end bracket.
The EMIC also has a self-diagnostic actuator test
capability, which will test each of the PCI bus mes-
sage-controlled functions of the cluster by lighting
the appropriate indicators (except the airbag indica-
tor), sweeping the gauge needles to several calibra-
tion points across the gauge faces, and stepping the
odometer display sequentially from all ones through
all nines. (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). See the
owner's manual in the vehicle glove box for more
information on the features, use and operation of the
EMIC.
GAUGES All gauges receive battery current
through the EMIC circuitry when the ignition switch
is in the On or Start positions. With the ignition
switch in the Off position battery current is not sup-
plied to any gauges, and the EMIC circuitry is pro-
grammed to move all of the gauge needles back to
the low end of their respective scales. Therefore, the
gauges do not accurately indicate any vehicle condi-
tion unless the ignition switch is in the On or Start
positions. All of the EMIC gauges, except the odome-
ter, are air core magnetic units. Two fixed electro-magnetic coils are located within each gauge. These
coils are wrapped at right angles to each other
around a movable permanent magnet. The movable
magnet is suspended within the coils on one end of a
pivot shaft, while the gauge needle is attached to the
other end of the shaft. One of the coils has a fixed
current flowing through it to maintain a constant
magnetic field strength. Current flow through the
second coil changes, which causes changes in its
magnetic field strength. The current flowing through
the second coil is changed by the EMIC circuitry in
response to messages received over the PCI data bus.
The gauge needle moves as the movable permanent
magnet aligns itself to the changing magnetic fields
created around it by the electromagnets.
The gauges are diagnosed using the EMIC self-di-
agnostic actuator test. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). Proper testing of the PCI data bus and
the electronic data bus message inputs to the EMIC
that control each gauge require the use of a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation. Specific operation details for each gauge may
be found elsewhere in this service information.
VACUUM-FLUORESCENT DISPLAY The Vacu-
um-Fluorescent Display (VFD) module is soldered to
the EMIC circuit board. The display is active when
the driver door is opened with the ignition switch in
the Off or Accessory positions (Rental Car mode), and
with the ignition switch in the On or Start positions.
The VFD is inactive when the ignition switch is in
the Off or Accessory positions and the driver door is
closed. The illumination intensity of the VFD is con-
trolled by the EMIC circuitry based upon electronic
dimming level messages received from the BCM over
the PCI data bus, and is synchronized with the illu-
mination intensity of other VFDs in the vehicle. The
BCM provides dimming level messages based upon
internal programming and inputs it receives from the
control knob and control ring on the left (lighting)
control stalk of the multi-function switch on the
steering column.
The VFD has several display capabilities including
odometer, trip odometer, and warning messages
whenever the appropriate conditions exist. The VFD
warning messages include:
²ªdoorº- indicating a door is ajar.
²ªgateº- indicating the tailgate is ajar.
²ªglassº- indicating the tailgate glass is ajar.
²ªlowashº- indicating that the washer fluid
level is low.
²ªno busº- indicating there is no PCI data bus
communication detected.
An odometer/trip odometer switch on the EMIC cir-
cuit board is used to control the display modes. This
switch is actuated manually by depressing the odom-
KJINSTRUMENT CLUSTER 8J - 5
INSTRUMENT CLUSTER (Continued)

eter/trip odometer switch button that extends
through the lower edge of the cluster lens, just right
of the speedometer. Actuating this switch momen-
tarily with the ignition switch in the On position will
toggle the VFD between the odometer and trip odom-
eter modes. Depressing the switch button for about
two seconds while the VFD is in the trip odometer
mode will reset the trip odometer value to zero. Hold-
ing this switch depressed while turning the ignition
switch from the Off position to the On position will
initiate the EMIC self-diagnostic actuator test. The
VFD will also display the cluster software version
level near the completion of the EMIC self-diagnostic
actuator test. Refer to the appropriate diagnostic
information for additional details on this VFD func-
tion.
The VFD is diagnosed using the EMIC self-diag-
nostic actuator test. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). Proper testing of the PCI data bus and
the electronic data bus message inputs to the EMIC
that control some of the VFD functions requires the
use of a DRBIIItscan tool. Refer to the appropriate
diagnostic information. Specific operation details for
the odometer, the trip odometer, and the various
warning message functions of the VFD may be found
elsewhere in this service information.
INDICATORS Indicators are located in various
positions within the EMIC and are all connected to
the EMIC circuit board. The turn signal indicators,
security indicator, washer fluid indicator, and coolant
low indicator (diesel engine only) use hard wired
inputs to the EMIC. The brake indicator is controlled
by PCI data bus messages from the Controller
Antilock Brake (CAB) as well as by hard wired park
brake switch and brake fluid level switch inputs to
the EMIC. The Malfunction Indicator Lamp (MIL) is
normally controlled by PCI data bus messages from
the Powertrain Control Module (PCM); however, if
the EMIC loses PCI data bus communication, the
EMIC circuitry will automatically turn the MIL on
until PCI data bus communication is restored. The
EMIC uses PCI data bus messages from the Body
Control Module (BCM), the PCM, the Airbag Control
Module (ACM), and the CAB to control all of the
remaining indicators.
The various indicators are controlled by different
strategies; some receive fused ignition switch output
from the EMIC circuitry and have a switched ground,
others are grounded through the EMIC circuitry and
have a switched battery feed, while still others are
completely controlled by the EMIC microprocessor
based upon various hard wired and electronic mes-
sage inputs. Some indicators are illuminated at a
fixed intensity, while the illumination intensity ofothers is synchronized with that of the EMIC general
illumination lamps.
In addition, certain indicators in this instrument
cluster are automatically configured or self-config-
ured. This feature allows the configurable indicators
to be enabled by the EMIC circuitry for compatibility
with certain optional equipment. The ABS indicator,
airbag indicator, SKIS indicator are automatically
configured by PCI data bus messages received by the
EMIC from the CAB, ACM, or Sentry Key Immobi-
lizer Module (SKIM) after the EMIC is installed in
the vehicle. Once these configuration settings are
learned by the EMIC, the DRBIIItscan tool must be
used to remove these settings from the EMIC non-
volatile memory. The self-configured indicators
remain latent in each EMIC at all times and will be
activated only when the EMIC receives the appropri-
ate PCI message inputs for the optional system or
equipment.
The hard wired indicators are diagnosed using con-
ventional diagnostic methods. The EMIC and PCI
bus message controlled indicators are diagnosed
using the EMIC self-diagnostic actuator test. (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DIAGNOSIS AND TESTING). Proper testing of the
PCI data bus and the electronic data bus message
inputs to the EMIC that control each indicator
require the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information. Specific details of
the operation for each indicator may be found else-
where in this service information.
CLUSTER ILLUMINATION The EMIC has several
illumination lamps that are illuminated when the
exterior lighting is turned on with the headlamp
(multi-function) switch. The illumination intensity of
these lamps is adjusted by a 12-volt Pulse Width
Modulated (PWM) output of the EMIC when the
interior lighting control ring on the left control stalk
of the multi-function switch is rotated (down to dim,
up to brighten) to one of six available minor detent
positions. The BCM provides electronic dimming
level messages based upon internal programming
and inputs it receives from the control knob and con-
trol ring on the left (lighting) control stalk of the
multi-function switch on the steering column, then
provides a control output to energize or de-energize
the park lamp relay as appropriate. The energized
park lamp relay provides battery current to the
EMIC on the hard wired fused park lamp relay out-
put circuit, and the BCM provides the electronic dim-
ming level message to the EMIC over the PCI data
bus. The EMIC electronic circuitry provides the
proper PWM output to the cluster illumination lamps
and the VFD on the EMIC circuit board, then pro-
vides a synchronized PWM output on the hard wired
8J - 6 INSTRUMENT CLUSTERKJ
INSTRUMENT CLUSTER (Continued)