2002 DODGE RAM airbag off

the front seat passenger can select a preferred level
of seat heating. Each heated seat switch has two
Light-Emitting Diode (LED) indicator lamps, which
indicate the selected mode (Low or High) of the seat
heater. These indicator lamps also provide diagnostic
feedback for the heated seat system. Each switch
also has an incandescent bulb, which provides dim-
mer controlled back lighting of the switch when the
headlamps or park lamps are on.
The two LED indicator lamps and the incandescent
bulb in each heated seat switch cannot be repaired. If
the indicator lamps or back lighting bulb are faulty
or damaged, the individual heated seat switch must
be replaced.
OPERATION
The heated seat switches receive battery current
through a fused ignition switch output (run) circuit
when the ignition switch is in the On position.
Depressing the heated seat switch rocker to its
momentary High or Low position provides a hard-
wired resistor multiplexed voltage request signal to
the heated seat module to power the heated seat ele-
ment of the selected seat and maintain the requested
temperature setting. If the heated seat switch is
depressed to a different position (Low or High) than
the currently selected state, the heated seat module
will change states to support the new selection. If a
heated seat switch is depressed a second time to thesame position as the currently selected state, the
heated seat module interprets the second input as a
request to turn the seat heater off. The heated seat
module will then turn the heated seat elements for
that seat off.
The indicator lamps in the heated seat switches
receive battery current through a fused ignition
switch output (run) circuit when the ignition switch
is in the On position. The ground side of each indi-
cator lamp is controlled by a separate (high or low/
driver or passenger) indicator lamp driver circuit by
the heated seat module. The heated seat module con-
trol of the switch indicator lamps also allows the
module to provide diagnostic feedback to the vehicle
operator to indicate monitored heated seat system
faults by flashing the indicator lamps on and off. One
side of the incandescent back lighting bulb in each
heated seat switch is connected to ground at all
times. The other side of the incandescent bulb is con-
nected to the fused panel lamps dimmer switch sig-
nal circuit. These bulbs are energized when the park
lamps or headlamps are turned on, and their illumi-
nation intensity is controlled by the panel lamps dim-
mer switch.
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH
Refer toWiring Diagramsfor the location of com-
plete heated seat system wiring diagrams.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
(1) If the problem being diagnosed involves inoper-
ative heated seat switch back lighting and the cluster
illumination lamps operate, go to Step 2. If the prob-
lem being diagnosed involves inoperative heated seat
switch back lighting and the cluster illumination
lamps are also inoperative, refer toInstrument
Clusterin the index of this service manual for the
proper cluster illumination lamps diagnosis and test-
ing procedures. If the problem being diagnosed
involves inoperative heated seat switch indicator
lamps and the heated seat elements do not heat,
refer to Step 4. If the problem being diagnosed
Fig. 17 Heated Seat Switches
1 - Driver Switch
2 - Passenger Switch
3 - Indicator Lamps
4 - Heated Seat Switch Bezel
BR/BEHEATED SEAT SYSTEM 8G - 17
PASSENGER SEAT HEATER SWITCH (Continued)

HORN
TABLE OF CONTENTS
page page
HORN
DESCRIPTION..........................1
OPERATION............................1
HORN
DESCRIPTION..........................2
OPERATION............................2
DIAGNOSIS AND TESTING - HORN..........2
REMOVAL.............................2
INSTALLATION..........................3
HORN RELAY
DESCRIPTION..........................3OPERATION............................3
DIAGNOSIS AND TESTING - HORN RELAY....3
REMOVAL.............................4
INSTALLATION..........................4
HORN SWITCH
DESCRIPTION..........................4
OPERATION............................5
DIAGNOSIS AND TESTING - HORN SWITCH . . . 5
REMOVAL.............................5
HORN
DESCRIPTION
An electric horn system is standard factory-in-
stalled equipment on this model. Two horn systems
are offered on this model. The standard equipment
horn system features a single low-note electromag-
netic horn unit, while the optional dual horn system
features one low-note horn unit and one high-note
horn unit. Both horn systems use a non-switched
source of battery current so that the system will
remain functional, regardless of the ignition switch
position. The horn system includes the following com-
ponents:
²Clockspring
²High-line or premium Central Timer Module
(CTM)
²Horn(s)
²Horn relay
²Horn switch
(Refer to 8 - ELECTRICAL/RESTRAINTS/CLOCK-
SPRING - DESCRIPTION) for more information on
this component. (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/BODY CONTROL/
CENTRAL TIMER MODUL - DESCRIPTION) for
more information on this component. Refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector 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. Following are general
descriptions of the remaining major components in
the horn system.
OPERATION
Each horn system is activated by a horn switch
concealed beneath the driver side airbag module trim
cover in the center of the steering wheel. Depressing
the center of the driver side airbag module trim cover
closes the horn switch. Closing the horn switch acti-
vates the horn relay. The activated horn relay then
switches the battery current needed to energize the
horn(s).
Refer to the owner's manual in the vehicle glove
box for more information on the features, use and
operation of the horn system.
CENTRAL TIMER MODULE
The high-line or premium Central Timer Module
(CTM) can also operate the horn system. A high-line
CTM is used on high-line versions of this vehicle. A
premium CTM is used on vehicles equipped with the
optional heated seats. The CTM combines the func-
tions of a chime/buzzer module, an intermittent wipe
module, an illuminated entry module, a remote key-
less entry module, and a vehicle theft security sys-
tem module in a single unit.
The high-line or premium CTM also controls and
integrates many of the additional electronic functions
and features included on models with this option.
The horn relay is one of the hard wired outputs of
the CTM. The high-line or premium CTM is pro-
grammed to energize or de-energize the horn relay in
response to certain inputs from the Vehicle Theft
Security System (VTSS) and/or the Remote Keyless
Entry (RKE) system.
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/BODY CONTROL/CENTRAL
TIMER MODUL - DESCRIPTION) for more informa-
tion on the high-line or premium CTM. (Refer to 8 -
BR/BEHORN 8H - 1

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

trol some of the VFD functions requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information. Specific operation details for the
odometer and trip odometer functions of the VFD
may be found elsewhere in this service manual.
INDICATORS
Indicators are located in various positions within
the EMIC and are all connected to the EMIC circuit
board. The four-wheel drive indicator, high beam
indicator, washer fluid indicator, turn signal indica-
tors, and wait-to-start indicator are hard wired. The
brake indicator is controlled by CCD data bus mes-
sages from the Controller Anti-lock Brake (CAB) and
the hard wired park brake switch input to the EMIC.
The seatbelt indicator is controlled by the EMIC pro-
gramming, CCD data bus messages from the Airbag
Control Module (ACM), and the hard wired seat belt
switch input to the EMIC. The Malfunction Indicator
Lamp (MIL) is normally controlled by CCD data bus
messages from the Powertrain Control Module
(PCM); however, if the EMIC loses CCD data bus
communications, the EMIC circuitry will automati-
cally turn the MIL on, and flash the odometer VFD
on and off repeatedly until CCD data bus communi-
cation is restored. The EMIC uses CCD data bus
messages from the Powertrain Control Module
(PCM), the diesel engine only Engine Control Module
(ECM), the ACM, and the CAB to control all of the
remaining indicators. Different indicators are con-
trolled by different strategies; some receive fused
ignition switch output from the EMIC circuitry clus-
ter and have a switched ground, while others are
grounded through the EMIC circuitry and have a
switched battery feed.
In addition, certain indicators in this instrument
cluster are programmable or configurable. This fea-
ture allows the programmable indicators to be acti-
vated or deactivated with a DRBIIItscan tool, while
the configurable indicators will be automatically
enabled or disabled by the EMIC circuitry for com-
patibility with certain optional equipment. The only
programmable indicator for this model is the upshift
indicator. The cruise indicator, four-wheel drive indi-
cator, overdrive-off indicator, service reminder indica-
tor, and the transmission overtemp indicator are
automatically configured, either electronically or
mechanically.
The hard wired indicators are diagnosed using con-
ventional diagnostic methods. The EMIC and CCD
bus message controlled indicator lamps are diagnosed
using the EMIC self-diagnostic actuator test. (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DIAGNOSIS AND TESTING). Proper testing of the
CCD data bus and the data bus message inputs to
the EMIC that control each indicator lamp requirethe use of a DRBIIItscan tool. Refer to the appro-
priate diagnostic information. Specific operation
details for each indicator may be found elsewhere in
this service manual.
CLUSTER ILLUMINATION
The EMIC has several illumination lamps that are
illuminated when the exterior lighting is turned on
with the headlamp switch. The illumination bright-
ness of these lamps is adjusted by the panel lamps
dimmer rheostat when the headlamp switch thumb-
wheel is rotated (down to dim, up to brighten). The
illumination lamps receive battery current through
the panel lamps dimmer rheostat and a fuse in the
JB on a fused panel lamps dimmer switch signal cir-
cuit. The illumination lamps are grounded at all
times.
In addition, an analog/digital (A/D) converter in
the EMIC converts the analog panel lamps dimmer
rheostat input from the headlamp switch to a digital
dimming level signal for controlling the lighting level
of the VFD. The EMIC also broadcasts this digital
dimming information as a message over the CCD
data bus for use by the Compass Mini-Trip Computer
(CMTC) in synchronizing the lighting level of its
VFD with that of the EMIC. The headlamp switch
thumbwheel also has a Parade position to provide a
parade mode. The EMIC monitors the request for
this mode through a hard wired day brightness sense
circuit input from the headlamp switch. In this mode,
the EMIC will override the selected panel dimmer
switch signal and send a message over the CCD data
bus to illuminate all vacuum fluorescent displays at
full brightness for easier visibility when driving in
daylight with the exterior lighting turned on. The
parade mode has no effect on the incandescent bulb
illumination intensity.
The hard wired cluster illumination lamps are
diagnosed using conventional diagnostic methods.
Proper testing of the VFD dimming level and the
CCD data bus dimming level message functions
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
CHIME WARNING REQUESTS
The EMIC is programmed to request chime service
from the Central Timer Module (CTM) when certain
indicator lamps are illuminated. When the pro-
grammed conditions are met, the EMIC generates a
chime request signal and sends it over a hard wired
tone request circuit to the CTM. Upon receiving the
proper chime request, the CTM activates an integral
chime tone generator to provide the audible chime
tone to the vehicle operator. (Refer to 8 - ELECTRI-
CAL/CHIME/BUZZER - OPERATION). Proper test-
ing of the CTM and the EMIC chime requests
BR/BEINSTRUMENT CLUSTER 8J - 5
INSTRUMENT CLUSTER (Continued)

requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
DIAGNOSIS AND TESTING - INSTRUMENT
CLUSTER
If all of the instrument cluster gauges and/or indi-
cators are inoperative, refer to PRELIMINARY
DIAGNOSIS . If an individual gauge or Chrysler Col-
lision Detection (CCD) data bus message-controlled
indicator is inoperative, refer to ACTUATOR TEST .
If an individual hard wired indicator is inoperative,
refer to the diagnosis and testing information for
that specific indicator. If the instrument cluster
chime warning request function is inoperative, refer
to CHIME WARNING REQUEST DIAGNOSIS . If
the instrument cluster illumination lighting is inop-
erative, refer to CLUSTER ILLUMINATION DIAG-
NOSIS . If the instrument cluster Vacuum-
Fluorescent Display (VFD) dimmer service is
inoperative, use a DRBIIItscan tool to diagnose the
problem. Refer to the appropriate diagnostic proce-
dures. Refer to the appropriate 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 connectors, splices and grounds.
NOTE: Certain indicators in this instrument cluster
are programmable. This feature allows those indica-
tors to be activated or deactivated with a DRBIIIT
scan tool for compatibility with certain optional
equipment. If the problem being diagnosed involves
improper illumination of the upshift indicator, use a
DRBIIITscan tool to be certain that the instrument
cluster has been programmed with the proper vehi-
cle equipment option settings.
PRELIMINARY DIAGNOSIS
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) If the indicators operate, but none of the
gauges operate, go to Step 2. If all of the gauges and
the CCD data bus message-controlled indicators are
inoperative, go to Step 5.
(2) Check the fused B(+) fuse (Fuse 14 - 10
ampere) in the Junction Block (JB). If OK, go to Step
3. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.
(3) Check for battery voltage at the fused B(+) fuse
(Fuse 14 - 10 ampere) in the JB. If OK, go to Step 4.
If not OK, repair the open fused B(+) circuit between
the JB and the Power Distribution Center (PDC) as
required.
(4) Disconnect and isolate the battery negative
cable. Remove the instrument cluster. Connect the
battery negative cable. Check for battery voltage at
the fused B(+) circuit cavity of the instrument panel
wire harness connector (Connector C1) for the instru-
ment cluster. If OK, refer to ACTUATOR TEST . If
not OK, repair the open fused B(+) circuit between
the instrument cluster and the JB as required.
(5) Check the fused ignition switch output (st-run)
fuse (Fuse 17 - 10 ampere) in the JB. If OK, go to
Step 6. If not OK, repair the shorted circuit or com-
ponent as required and replace the faulty fuse.
(6) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (st-run) fuse (Fuse 17 - 10 ampere) in the JB.
If OK, go to Step 7. If not OK, repair the open fused
ignition switch output (st-run) circuit between the
instrument cluster and the JB as required.
(7) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Reinstall the instrument cluster. Reconnect the bat-
tery negative cable. Turn the ignition switch to the
On position. Set the park brake. The brake indicator
in the instrument cluster should light. If OK, go to
Step 8. If not OK, go to Step 9.
(8) Turn the ignition switch to the Off position.
Turn on the park lamps and adjust the panel lamps
dimmer thumbwheel in the headlamp switch to the
full bright position. The cluster illumination lamps
should light. If OK, go to Step 10. If not OK, repair
the open ground circuit (Z3) between the instrument
cluster and ground (G201) as required.
(9) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the instrument cluster. Connect the battery
negative cable. Turn the ignition switch to the On
position. Check for battery voltage at the fused igni-
tion switch output (st-run) circuit cavity of the
instrument panel wire harness connector (Connector
C1). If OK, refer to ACTUATOR TEST . If not OK,
repair the open fused ignition switch output (st-run)
circuit between the instrument cluster and the JB as
required.
8J - 6 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

(10) Disconnect and isolate the battery negative
cable. Remove the instrument cluster. Check for con-
tinuity between the ground circuit (Z2) cavity of the
instrument panel wire harness connector (Connector
C1) and a good ground. There should be continuity. If
OK, refer to ACTUATOR TEST . If not OK, repair
the open ground circuit to ground (G200) as required.
ACTUATOR TEST
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.
The instrument cluster actuator test will put the
instrument cluster into its self-diagnostic mode. In
this mode the instrument cluster can perform a self-
diagnostic test that will confirm that the instrument
cluster circuitry, the gauges, and the CCD data bus
message-controlled indicators are capable of operat-
ing as designed. During the actuator test the instru-
ment cluster circuitry position each of the gaugeneedles at various calibration points, illuminate each
of the segments in the Vacuum-Fluorescent Display
(VFD), and turn all of the CCD data bus message-
controlled indicators on and off.
Successful completion of the actuator test will con-
firm that the instrument cluster is operational. How-
ever, there may still be a problem with the CCD data
bus, the Powertrain Control Module (PCM), the
Engine Control Module (ECM), the Airbag Control
Module (ACM), the Controller Anti-lock Brake (CAB),
or the inputs to one of these electronic control mod-
ules. Use a DRBIIItscan tool to diagnose these com-
ponents. Refer to the appropriate diagnostic
information.
(1) Begin the test with the ignition switch in the
Off position.
(2) Depress the odometer/trip odometer switch but-
ton.
(3) While still holding the odometer/trip odometer
switch button depressed, turn the ignition switch to
the On position, but do not start the engine.
(4) Keep the odometer/trip odometer switch button
depressed for about ten seconds, untilCHEC
appears in the odometer display, then release the
odometer/trip odometer switch button.
(5) A series of three-digit numeric failure messages
may appear in the odometer display, depending upon
the failure mode. If a failure message appears, refer
to the Instrument Cluster Failure Message chart for
the description and proper correction. If no failure
message appears, the actuator test will proceed as
described in Step 6.
INSTRUMENT CLUSTER FAILURE MESSAGE
Message Description Correction
110 A failure has been identified in the cluster
CPU, RAM, or EEPROM.1. Replace the faulty cluster.
900 The CCD data bus is not operational. 1. Check the CCD data bus connections at the
cluster.
2. Check the cluster fuses.
3. Check the CCD data bus bias.
4. Check the CCD data bus voltage.
5. Check the CCD data bus terminations.
920 The cluster is not receiving a vehicle speed
message from the PCM.1. Check the PCM software level and reflash if
required.
2. Use a DRBIIITscan tool to verify that the
vehicle speed message is being sent by the
PCM.
921 The cluster is not receiving a distance pulse
message from the PCM.1. Check the PCM software level and reflash if
required.
2. Use a DRBIIITscan tool to verify that the
distance pulse message is being sent by the
PCM.
BR/BEINSTRUMENT CLUSTER 8J - 7
INSTRUMENT CLUSTER (Continued)

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)