2002 DODGE RAM ABS

INSTRUMENT CLUSTER
TABLE OF CONTENTS
page page
INSTRUMENT CLUSTER
DESCRIPTION..........................2
OPERATION............................3
DIAGNOSIS AND TESTING - INSTRUMENT
CLUSTER............................6
REMOVAL.............................10
DISASSEMBLY.........................10
ASSEMBLY............................12
INSTALLATION.........................13
ABS INDICATOR
DESCRIPTION.........................14
OPERATION...........................14
AIRBAG INDICATOR
DESCRIPTION.........................15
OPERATION...........................15
BRAKE/PARK BRAKE INDICATOR
DESCRIPTION.........................15
OPERATION...........................15
DIAGNOSIS AND TESTING - BRAKE
INDICATOR..........................16
CHECK GAUGES INDICATOR
DESCRIPTION.........................17
OPERATION...........................17
CRUISE INDICATOR
DESCRIPTION.........................18
OPERATION...........................18
ENGINE TEMPERATURE GAUGE
DESCRIPTION.........................18
OPERATION...........................19
FUEL GAUGE
DESCRIPTION.........................19
OPERATION...........................20
GEAR SELECTOR INDICATOR
DESCRIPTION.........................20
OPERATION...........................21
HIGH BEAM INDICATOR
DESCRIPTION.........................21
OPERATION...........................21
DIAGNOSIS AND TESTING - HIGH BEAM
INDICATOR..........................21
LOW FUEL INDICATOR
DESCRIPTION.........................22
OPERATION...........................22
MALFUNCTION INDICATOR LAMP MIL
DESCRIPTION.........................23
OPERATION...........................23
ODOMETER
DESCRIPTION.........................24
OPERATION...........................24OIL PRESSURE GAUGE
DESCRIPTION.........................25
OPERATION...........................25
OVERDRIVE OFF INDICATOR
DESCRIPTION.........................26
OPERATION...........................26
SEATBELT INDICATOR
DESCRIPTION.........................27
OPERATION...........................27
SERVICE REMINDER INDICATOR
DESCRIPTION.........................27
OPERATION...........................28
SHIFT INDICATOR (TRANSFER CASE)
DESCRIPTION.........................28
OPERATION...........................28
DIAGNOSIS AND TESTING - FOUR-WHEEL
DRIVE INDICATOR....................29
SPEEDOMETER
DESCRIPTION.........................29
OPERATION...........................30
TACHOMETER
DESCRIPTION.........................30
OPERATION...........................30
TRANS OVERTEMP INDICATOR
DESCRIPTION.........................31
OPERATION...........................31
TURN SIGNAL INDICATOR
DESCRIPTION.........................32
OPERATION...........................32
DIAGNOSIS AND TESTING - TURN SIGNAL
INDICATOR..........................32
UPSHIFT INDICATOR
DESCRIPTION.........................32
OPERATION...........................33
VOLTAGE GAUGE
DESCRIPTION.........................33
OPERATION...........................33
WAIT-TO-START INDICATOR
DESCRIPTION.........................34
OPERATION...........................34
WASHER FLUID INDICATOR
DESCRIPTION.........................35
OPERATION...........................35
DIAGNOSIS AND TESTING - WASHER FLUID
INDICATOR..........................35
WATER-IN-FUEL INDICATOR
DESCRIPTION.........................36
OPERATION...........................36
BR/BEINSTRUMENT CLUSTER 8J - 1

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 EMIC gauges and indicators are
protected by an integral clear plastic cluster lens,
and are visible through a dedicated opening in the
cluster bezel on the instrument panel. Just behind
the cluster lens is the cluster hood. The cluster hood
serves as a visor and shields the face of the cluster
from ambient light and reflections to reduce glare.
Behind the cluster hood is the cluster overlay and
gauges. The overlay is a multi-layered unit. The
dark, visible surface of the outer layer of the overlay
is marked with all of the gauge identification 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 trans-
lucence of this layer allows those indicators and icons
that are illuminated to be readily visible. The under-
lying 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. On the
lower edge of the cluster lens just left of center, the
odometer/trip odometer switch knob protrudesthrough a dedicated hole in the lens. The remainder
of the EMIC, including the mounts and the electrical
connections, are concealed behind the cluster bezel.
The molded plastic EMIC housing has four integral
mounting tabs, two each on the upper and lower
edges of the housing. The EMIC is secured to the
molded plastic instrument panel cluster carrier with
four screws. All electrical connections to the EMIC
are made at the back of the cluster housing through
two take outs of the instrument panel wire harness,
each equipped with a self-docking connector.
A single EMIC module is offered on this model.
This module utilizes integrated circuitry and infor-
mation carried on the Chrysler Collision Detection
(CCD) data bus network for control of all gauges and
many of the indicators. (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/COMMUNI-
CATION - DESCRIPTION). The EMIC also uses
several hard wired inputs in order to perform its
many functions. In addition to instrumentation and
indicators, the EMIC has hardware and/or software
to support the following functions:
²Chime Warning Requests- The EMIC sends
chime tone requests over a hard wired circuit to the
Central Timer Module (CTM) when it monitors cer-
tain conditions or inputs. The CTM replaces the
chime or buzzer module and performs the functions
necessary to provide audible alerts that are synchro-
nized with the visual alerts provided by the EMIC.
(Refer to 8 - ELECTRICAL/CHIME/BUZZER -
DESCRIPTION).
²Vacuum Fluorescent Display (VFD) Dim-
ming Service- The EMIC performs the functions
necessary to eliminate the need for a separate VFD
dimming module by providing control and synchroni-
zation of the illumination intensity of all vacuum flu-
orescent displays in the vehicle, as well as a parade
mode.
The EMIC module incorporates a blue-green digital
VFD for displaying odometer and trip odometer infor-
mation, as well as the amber cruise-on indicator dis-
play function. Some variations of the EMIC are
necessary to support optional equipment and regula-
tory requirements. The EMIC includes the following
analog gauges:
²Coolant Temperature Gauge
²Fuel Gauge
²Oil Pressure Gauge
²Speedometer
²Tachometer
²Voltage Gauge
The EMIC also includes provisions for the follow-
ing indicators:
²Airbag Indicator
²Antilock Brake System (ABS) Indicator
²Brake Indicator
Fig. 1 Instrument Cluster Components
1 - COVER
2 - HOUSING
3 - MASK AND GAUGES
4 - HOOD
5 - LENS
6 - CIRCUIT BOARD
7 - ODOMETER RESET BUTTON
8J - 2 INSTRUMENT CLUSTERBR/BE

INSTRUMENT CLUSTER FAILURE MESSAGE
Message Description Correction
940 The cluster is not receiving an airbag lamp-on
message from the ACM.1. Check the CCD data bus connections at the
ACM.
2. Check the ACM fuse.
950 The cluster is not receiving an ABS lamp-on
message from the CAB.1. Check the CCD data bus connections at the
CAB.
2. Check the CAB fuse.
999 An error has been discovered. 1. Record the failure message.
2. Depress the trip odometer reset button to
continue the Self-Diagnostic Test.
(6) The instrument cluster will begin the Vacuum
Fluorescent Display (VFD) walking segment test.
This test will require the operator to visually inspect
each VFD segment as it is displayed to determine a
pass or fail condition. First, all of the segments will
be illuminated at once; then, each individual segment
of the VFD will be illuminated in sequence. If any
segment in the display fails to illuminate, repeat the
test to confirm the failure. If the failure is confirmed,
replace the faulty instrument cluster. Following com-
pletion of the VFD walking segment test, the actua-
tor test will proceed as described in Step 7.
(7) The instrument cluster will perform a bulb
check of each indicator that the instrument cluster
circuitry controls. If the wait-to-start indicator does
not illuminate during this test, the instrument clus-
ter should be removed. However, check that the
incandescent bulb is not faulty and that the bulb
holder is properly installed on the instrument cluster
electronic circuit board before considering instrument
cluster replacement. If the bulb and bulb holder
check OK, replace the faulty instrument cluster.
Each of the remaining instrument cluster circuitry
controlled indicators except the cruise indicator are
illuminated by a Light Emitting Diode (LED). If an
LED or the cruise indicator in the VFD, fails to illu-
minate during this test, the instrument cluster must
be replaced. Following the bulb check test, the actua-
tor test will proceed as described in Step 8.
(8) The instrument cluster will perform a gauge
actuator test. In this test the instrument cluster cir-
cuitry positions each of the gauge needles at three
different calibration points, then returns the gauge
needles to their relaxed positions. If an individual
gauge does not respond properly, or does not respondat all during the gauge actuator test, the instrument
cluster should be removed. However, check that the
gauge terminal pins are properly inserted through
the spring-clip terminal pin receptacles on the instru-
ment cluster electronic circuit board before consider-
ing instrument cluster replacement. If the gauge
terminal connections are OK, replace the faulty
instrument cluster.
(9) The actuator test is now completed. The instru-
ment cluster will automatically exit the self-diagnos-
tic mode and return to normal operation at the
completion of the test, if the ignition switch is turned
to the Off position during the test, or if a vehicle
speed message indicating that the vehicle is moving
is received from the PCM on the CCD data bus dur-
ing the test.
(10) Go back to Step 1 to repeat the test, if
required.
CHIME WARNING REQUEST DIAGNOSIS
Before performing this test, complete the testing of
the seat belt switch and the Central Timer Module
(CTM). (Refer to 8 - ELECTRICAL/RESTRAINTS/
SEAT BELT SWITCH - DIAGNOSIS AND TESTING)
and (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/BODY CONTROL/CENTRAL
TIMER MODULE - DIAGNOSIS AND TESTING).
The diagnosis found here consists of confirming the
viability of the hard wired tone request circuit
between the instrument cluster and the Central
Timer Module (CTM). For diagnosis of the CCD data
bus and the data bus message inputs that cause the
instrument cluster to issue a request for chime ser-
vice, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
8J - 8 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, 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.
GEAR SELECTOR INDICATOR
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument cluster from the instru-
ment panel. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - REMOVAL).
(3) Remove the steering column opening cover
from the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).
(4) Reach through the instrument panel steering
column opening to access and disengage the loop end
of the gear selector indicator cable from the PRNDL
driver lever on the left side of the steering column
(Fig. 4).(5) Squeeze the sides of the plastic adjuster and
bracket unit to disengage the tabs that secure it to
the sides of the steering column window.
(6) Remove the gear selector indicator mechanism
and cable unit through the instrument panel cluster
opening.
CLUSTER BULB
This procedure applies to each of the incandescent
cluster illumination lamp or indicator lamp bulb and
bulb holder units. However, the illumination lamps
and the indicator lamps use different bulb and bulb
holder unit sizes. They must never be interchanged.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument cluster from the instru-
ment panel. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - REMOVAL).
(3) Turn the bulb holder counterclockwise about
sixty degrees on the cluster electronic circuit board
(Fig. 5).
(4) Pull the bulb and bulb holder unit straight
back to remove it from the bulb mounting hole in the
cluster electronic circuit board.
CLUSTER LENS AND HOOD
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument cluster from the instru-
ment panel. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - REMOVAL).
Fig. 4 Gear Selector Indicator Cable Remove/Install
1 - STEERING COLUMN
2 - CABLE
3 - LOOP END
4 - LEVER
5 - ADJUSTER AND BRACKET
Fig. 5 Cluster Bulb Remove/Install
1 - INSTRUMENT CLUSTER
2 - BULB AND HOLDER
BR/BEINSTRUMENT CLUSTER 8J - 11
INSTRUMENT CLUSTER (Continued)

(3) Remove the seven screws that secure the lens
and hood unit to the cluster housing (Fig. 6).
(4) Gently pull the lens and hood unit away from
the cluster housing.
CAUTION: Do not touch the face of the gauge over-
lay or the back of the cluster lens with your finger.
It will leave a permanent finger print.
CLUSTER HOUSING REAR COVER
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument cluster from the instru-
ment panel. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - REMOVAL).
(3) Remove the six screws that secure the rear
cover to the back of the cluster housing (Fig. 7).
(4) Remove the rear cover from the back of the
cluster housing.
CLUSTER HOUSING
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument cluster from the instru-
ment panel. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - REMOVAL).
(3) Remove the lens and hood unit from the cluster
housing. Refer to CLUSTER LENS AND HOOD .
(4) Remove the rear cover from the cluster hous-
ing. Refer to CLUSTER HOUSING REAR COVER .
ASSEMBLY
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, 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.
GEAR SELECTOR INDICATOR
(1) Position the gear selector indicator mechanism
and cable unit into the instrument panel cluster
opening.
(2) Route the cable through the instrument panel
and under the steering column to the PRNDL driver
lever on the left side of the steering column.
(3) Squeeze the sides of the plastic adjuster and
bracket unit and engage the tabs that secure it with
the sides of the steering column window.
(4) Engage the loop end of the gear selector indi-
cator cable onto the PRNDL driver lever on the left
side of the steering column (Fig. 4).
(5) Reinstall the instrument cluster onto the
instrument panel. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - INSTALLATION).
(6) Confirm proper operation of the gear selector
indicator. Calibrate the indicator, if required. (Refer
to 19 - STEERING/COLUMN - INSTALLATION).
(7) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-Fig. 6 Instrument Cluster Components
1 - COVER
2 - HOUSING
3 - MASK AND GAUGES
4 - HOOD
5 - LENS
6 - CIRCUIT BOARD
7 - ODOMETER RESET BUTTON
Fig. 7 Cluster Housing Rear Cover Remove/Install
1 - REAR CLUSTER HOUSING COVER
8J - 12 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

(Refer to 19 - STEERING/COLUMN - INSTALLA-
TION).
(8) Reconnect the battery negative cable.
NOTE: Some of the indicators in this instrument
cluster are either programmable (upshift indicator)
or automatically configured (cruise, overdrive-off,
and transmission overtemp indicators) when the
cluster is connected to the vehicle electrical sys-
tem. This feature allows those indicator lamps to be
enabled or disabled for compatibility with certain
optional equipment. If a new instrument cluster is
being installed, use a DRBIIITscan tool to program
the instrument cluster with the proper vehicle
equipment option setting to enable and/or disable
the upshift indicator lamp. Refer to the appropriate
diagnostic information.
ABS INDICATOR
DESCRIPTION
An Antilock Brake System (ABS) indicator is stan-
dard equipment on all instrument clusters. This indi-
cator serves both the standard equipment Rear
Wheel Anti-Lock (RWAL) and optional equipment
4-Wheel Anti-Lock (4WAL) brake systems. The ABS
indicator is located near the lower edge of the instru-
ment cluster overlay, to the left of center. The ABS
indicator consists of a stencilled cutout of the Inter-
national Control and Display Symbol icon for ªFail-
ure of Anti-lock Braking Systemº in the opaque layer
of the instrument cluster overlay. The dark outer
layer of the overlay prevents the indicator from being
clearly visible when it is not illuminated. An amber
lens behind the cutout in the opaque layer of the
overlay causes the icon to appear in amber through
the translucent outer layer of the overlay when it is
illuminated from behind by a Light Emitting Diode
(LED) soldered onto the instrument cluster electronic
circuit board. The ABS indicator is serviced as a unit
with the instrument cluster.
OPERATION
The ABS indicator gives an indication to the vehi-
cle operator when the ABS system is faulty or inop-
erative. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Chrysler Collision Detection (CCD) data bus.
The ABS indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, theLED will always be off when the ignition switch is in
any position except On or Start. The LED only illu-
minates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the ABS indicator for the following rea-
sons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ABS indicator is illu-
minated by the cluster for about two seconds as a
bulb test.
²ABS Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the CAB, the
ABS indicator will be illuminated. The indicator
remains illuminated until the cluster receives a
lamp-off message from the CAB, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Communication Error- If the cluster receives
no lamp-on or lamp-off messages from the CAB for
six consecutive seconds, the ABS indicator is illumi-
nated. The indicator remains illuminated until the
cluster receives a valid message from the CAB, or
until the ignition switch is turned to the Off position,
whichever occurs first.
²Actuator Test- Each time the instrument clus-
ter is put through the actuator test, the ABS indica-
tor will be turned on during the bulb check portion of
the test to confirm the functionality of the LED and
the cluster control circuitry.
²ABS Diagnostic Test- The ABS indicator is
blinked on and off by lamp-on and lamp-off messages
from the CAB during the performance of the ABS
diagnostic tests.
The CAB continually monitors the ABS circuits
and sensors to decide whether the system is in good
operating condition. The CAB then sends the proper
lamp-on or lamp-off messages to the instrument clus-
ter. If the CAB sends a lamp-on message after the
bulb test, it indicates that the CAB has detected a
system malfunction and/or that the ABS system has
become inoperative. The CAB will store a Diagnostic
Trouble Code (DTC) for any malfunction it detects.
Each time the ABS indicator fails to light due to an
open or short in the cluster ABS indicator circuit, the
cluster sends a message notifying the CAB of the
condition, and the CAB will store a DTC. For proper
diagnosis of the antilock brake system, the CAB, the
CCD data bus, or the message inputs to the instru-
ment cluster that control the ABS indicator, a
DRBIIItscan tool is required. Refer to the appropri-
ate diagnostic information.
8J - 14 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

on the instrument cluster circuit board based upon a
hard wired input to the instrument cluster, cluster
programming, and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Chrysler Collision Detection (CCD) data bus.
The brake indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, the
LED will always be off when the ignition switch is in
any position except On or Start. The LED only illu-
minates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the brake indicator for the following rea-
sons:
²Bulb Test- Each time the ignition switch is
turned to the On position the brake indicator is illu-
minated by the instrument cluster for about four sec-
onds as a bulb test.
²Park Brake-On- If the park brake is applied
or not fully released with the ignition switch in the
On position, the brake indicator is illuminated solid.
The brake indicator will blink on and off repeatedly
when the park brake is applied or not fully released
and the ignition switch is in the On position if a
vehicle with an automatic transmission is not in
Park or Neutral, or if the engine is running on vehi-
cles with a manual transmission.
²Brake Lamp-On Message- Each time the
cluster receives a lamp-on message from the CAB,
the brake indicator will be illuminated. The indicator
remains illuminated until the cluster receives a
lamp-off message from the CAB, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Actuator Test- Each time the instrument clus-
ter is put through the actuator test, the brake indi-
cator will be turned on during the bulb check portion
of the test to confirm the functionality of the LED
and the cluster control circuitry.
The park brake switch on the park brake pedal
mechanism provides a hard wired ground input to
the instrument cluster circuitry through the park
brake switch sense circuit whenever the park brake
is applied or not fully released. The CAB continually
monitors the brake pressure switch on the brake
combination valve to determine if the pressures in
the two halves of the split brake hydraulic system
are unequal. The CAB then sends the proper lamp-on
or lamp-off messages to the instrument cluster. If the
CAB sends a lamp-on message after the bulb test, it
indicates that the CAB has detected a brake hydrau-
lic system malfunction and/or that the ABS system
has become inoperative. The CAB will store a Diag-
nostic Trouble Code (DTC) for any malfunction itdetects. The park brake switch input to the instru-
ment cluster can be diagnosed using conventional
diagnostic tools and methods. For proper diagnosis of
the antilock brake system, the CAB, the CCD data
bus, or the message inputs to the instrument cluster
that control the brake indicator, a DRBIIItscan tool
is required. Refer to the appropriate diagnostic infor-
mation.
DIAGNOSIS AND TESTING - BRAKE INDICATOR
The diagnosis found here addresses an inoperative
brake indicator condition. If the brake indicator
comes on or stays on with the ignition switch in the
On position and the park brake released, or comes on
while driving, the brake system must be diagnosed
and repaired prior to performing the following tests.
(Refer to 5 - BRAKES - DIAGNOSIS AND TEST-
ING). If no brake system problem is found, the fol-
lowing procedure will help locate a faulty park brake
switch or park brake switch sense circuit. Refer to
the appropriate wiring information. The wiring infor-
mation 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 con-
nectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, 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. Disconnect the instrument panel wire harness
connector for the park brake switch from the switch
terminal. With the park brake released, check for
continuity between the park brake switch terminal
and a good ground. There should be no continuity. If
OK, go to Step 2. If not OK, adjust or replace the
faulty park brake switch.
(2) Remove the instrument cluster from the instru-
ment panel. With the park brake switch still discon-
nected, check for continuity between the park brake
switch sense circuit cavity of the instrument panel
wire harness connector for the park brake switch and
a good ground. There should be no continuity. If OK,
go to Step 3. If not OK, repair the shorted park
8J - 16 INSTRUMENT CLUSTERBR/BE
BRAKE/PARK BRAKE INDICATOR (Continued)

to the location of the fuel filler access. The fuel gauge
graphics are white against a black field except for a
single red graduation at the low end of the gauge
scale, making them clearly visible within the instru-
ment cluster in daylight. When illuminated from
behind by the panel lamps dimmer controlled cluster
illumination lighting with the exterior lamps turned
On, the white graphics appear blue-green and the
red graphics appear red. The orange gauge needle is
internally illuminated. Gauge illumination is pro-
vided by replaceable incandescent bulb and bulb
holder units located on the instrument cluster elec-
tronic circuit board. The fuel gauge is serviced as a
unit with the instrument cluster.
OPERATION
The fuel gauge gives an indication to the vehicle
operator of the level of fuel in the fuel tank. This
gauge is controlled by the instrument cluster circuit
board based upon the cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Chrysler
Collision Detection (CCD) data bus. The fuel gauge is
an air core magnetic unit that receives battery cur-
rent on the instrument cluster electronic circuit
board through the fused ignition switch output (st-
run) circuit whenever the ignition switch is in the On
or Start positions. The cluster is programmed to
move the gauge needle back to the low end of the
scale after the ignition switch is turned to the Off
position. The instrument cluster circuitry controls
the gauge needle position and provides the following
features:
²Percent Tank Full Message- Each time the
cluster receives a message from the PCM indicating
the percent tank full, the cluster programming
applies an algorithm to calculate the proper gauge
needle position, then moves the gauge needle to the
proper position on the gauge scale. The algorithm is
used to dampen gauge needle movement against the
negative effect that fuel sloshing within the fuel tank
can have on accurate inputs from the fuel tank send-
ing unit to the PCM.
²Less Than 12.5 Percent Tank Full Message-
Each time the cluster receives messages from the
PCM indicating the percent tank full is 12.5 (one-
eighth) or less for 10 consecutive seconds and the
vehicle speed is zero, or for 60 consecutive seconds
and the vehicle speed is greater than zero, the gauge
needle is moved to the proper position on the gauge
scale, the low fuel indicator is illuminated, and a sin-
gle chime tone is sounded. The low fuel indicator
remains illuminated until the cluster receives mes-
sages from the PCM indicating that the percent tank
full is greater than 12.5 (one-eighth) for 10 consecu-
tive seconds and the vehicle speed is zero, or for 60consecutive seconds and the vehicle speed is greater
than zero, or until the ignition switch is turned to
the Off position, whichever occurs first. The chime
tone feature will only repeat during the same igni-
tion cycle if the low fuel indicator is cycled off and
then on again by the appropriate percent tank full
messages from the PCM.
²Less Than Empty Percent Tank Full Mes-
sage- Each time the cluster receives a message from
the PCM indicating the percent tank full is less than
empty, the gauge needle is moved to the far left (low)
end of the gauge scale and the low fuel indicator is
illuminated immediately. This message would indi-
cate that the fuel tank sender input to the PCM is a
short circuit.
²More Than Full Percent Tank Full Message
- Each time the cluster receives a message from the
PCM indicating the percent tank full is more than
full, the gauge needle is moved to the far left (low)
end of the gauge scale and the low fuel indicator is
illuminated immediately. This message would indi-
cate that the fuel tank sender input to the PCM is an
open circuit.
²Message Failure- If the cluster fails to receive
a percent tank full message, it will hold the gauge
needle at the last indication until a new message is
received, or until the ignition switch is turned to the
Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept to several calibration points on the gauge scale
in a prescribed sequence in order to confirm the func-
tionality of the gauge and the cluster control cir-
cuitry.
The PCM continually monitors the fuel tank send-
ing unit, then sends the proper messages to the
instrument cluster. For further diagnosis of the fuel
gauge or the instrument cluster circuitry that con-
trols the gauge, (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the fuel tank sending unit,
the PCM, the CCD data bus, or the message inputs
to the instrument cluster that control the fuel gauge,
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.
GEAR SELECTOR INDICATOR
DESCRIPTION
A mechanical automatic transmission gear selector
indicator is standard factory-installed equipment on
this model, when it is also equipped with an optional
automatic transmission. The gear selector indicator
consists of a molded black plastic housing with inte-
gral mounting tabs that is secured to the back of the
8J - 20 INSTRUMENT CLUSTERBR/BE
FUEL GAUGE (Continued)