ignition DODGE RAM 2001 Service Owners Manual

COLD FOULING/CARBON FOULING
Cold fouling is sometimes referred to as carbon
fouling. The deposits that cause cold fouling are basi-
cally carbon (Fig. 29). A dry, black deposit on one or
two plugs in a set may be caused by sticking valves
or defective spark plug cables. Cold (carbon) fouling
of the entire set of spark plugs may be caused by a
clogged air cleaner element or repeated short operat-
ing times (short trips).
WET FOULING OR GAS FOULING
A spark plug coated with excessive wet fuel or oil
is wet fouled. In older engines, worn piston rings,
leaking valve guide seals or excessive cylinder wear
can cause wet fouling. In new or recently overhauled
engines, wet fouling may occur before break-in (nor-
mal oil control) is achieved. This condition can usu-
ally be resolved by cleaning and reinstalling the
fouled plugs.
OIL OR ASH ENCRUSTED
If one or more spark plugs are oil or oil ash
encrusted (Fig. 30), evaluate engine condition for the
cause of oil entry into that particular combustion
chamber.
ELECTRODE GAP BRIDGING
Electrode gap bridging may be traced to loose
deposits in the combustion chamber. These deposits
accumulate on the spark plugs during continuous
stop-and-go driving. When the engine is suddenly
subjected to a high torque load, deposits partially liq-
uefy and bridge the gap between electrodes (Fig. 31).This short circuits the electrodes. Spark plugs with
electrode gap bridging can be cleaned using standard
procedures.
SCAVENGER DEPOSITS
Fuel scavenger deposits may be either white or yel-
low (Fig. 32). They may appear to be harmful, but
this is a normal condition caused by chemical addi-
tives in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Notice that accumula-
tion on the ground electrode and shell area may be
heavy, but the deposits are easily removed. Spark
plugs with scavenger deposits can be considered nor-
mal in condition and can be cleaned using standard
procedures.
Fig. 30 Oil or Ash Encrusted
Fig. 31 Electrode Gap Bridging
1 - GROUND ELECTRODE
2 - DEPOSITS
3 - CENTER ELECTRODE
Fig. 32 Scavenger Deposits
1 - GROUND ELECTRODE COVERED WITH WHITE OR
YELLOW DEPOSITS
2 - CENTER ELECTRODE
BR/BEIGNITION CONTROL 8I - 17
SPARK PLUG (Continued)

CHIPPED ELECTRODE INSULATOR
A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation can also separate the insulator
from the center electrode (Fig. 33). Spark plugs with
this condition must be replaced.
PREIGNITION DAMAGE
Preignition damage is usually caused by excessive
combustion chamber temperature. The center elec-
trode dissolves first and the ground electrode dis-
solves somewhat latter (Fig. 34). Insulators appear
relatively deposit free. Determine if the spark plug
has the correct heat range rating for the engine.
Determine if ignition timing is over advanced or if
other operating conditions are causing engine over-
heating. (The heat range rating refers to the operat-
ing temperature of a particular type spark plug.
Spark plugs are designed to operate within specific
temperature ranges. This depends upon the thick-
ness and length of the center electrodes porcelain
insulator.)
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
35). The increase in electrode gap will be consider-
ably in excess of 0.001 inch per 2000 miles of opera-
tion. This suggests that a plug with a cooler heat
range rating should be used. Over advanced ignition
timing, detonation and cooling system malfunctions
can also cause spark plug overheating.
REMOVAL
On 3.9L/5.2L/5.9L engines, spark plug cable heat
shields are pressed into the cylinder head to sur-
round each cable boot and spark plug (Fig. 36).
(1) Always remove spark plug or ignition coil
cables by grasping at the cable boot (Fig. 38). Turn
the cable boot 1/2 turn and pull straight back in a
steady motion. Never pull directly on the cable.
Internal damage to cable will result.
(2) Prior to removing the spark plug, spray com-
pressed air around the spark plug hole and the area
around the spark plug. This will help prevent foreign
material from entering the combustion chamber.
(3) Remove the spark plug using a quality socket
with a rubber or foam insert.
(4) Inspect the spark plug condition. Refer to
Spark Plug Condition in the Diagnostics and Testing
section of this group.
Fig. 33 Chipped Electrode Insulator
1 - GROUND ELECTRODE
2 - CENTER ELECTRODE
3 - CHIPPED INSULATOR
Fig. 34 Preignition Damage
1 - GROUND ELECTRODE STARTING TO DISSOLVE
2 - CENTER ELECTRODE DISSOLVED
Fig. 35 Spark Plug Overheating
1 - BLISTERED WHITE OR GRAY COLORED INSULATOR
8I - 18 IGNITION CONTROLBR/BE
SPARK PLUG (Continued)

CLEANING
The plugs may be cleaned using commercially
available spark plug cleaning equipment. After clean-
ing, file center electrode flat with a small point file or
jewelers file before adjusting gap.
CAUTION: Never use a motorized wire wheel brush
to clean spark plugs. Metallic deposits will remain
on spark plug insulator and will cause plug misfire.
INSTALLATION
Special care should be taken when installing spark
plugs into the cylinder head spark plug wells. Be
sure the plugs do not drop into the plug wells as elec-
trodes can be damaged.
Always tighten spark plugs to the specified torque.
Over tightening can cause distortion resulting in a
change in the spark plug gap or a cracked porcelain
insulator.
When replacing the spark plug and ignition coil
cables, route the cables correctly and secure them in
the appropriate retainers. Failure to route the cables
properly can cause the radio to reproduce ignition
noise. It could cause cross ignition of the spark plugs
or short circuit the cables to ground.
(1) Start the spark plug into the cylinder head by
hand to avoid cross threading.
(2) Tighten spark plugs to 35-41 N´m (26-30 ft.
lbs.) torque.
(3) Install spark plug cables over spark plugs.
SPARK PLUG CABLE
DESCRIPTION
Spark plug cables are sometimes referred to as sec-
ondary ignition wires.
OPERATION
The spark plug cables transfer electrical current
from the ignition coil(s) and/or distributor, to individ-
ual spark plugs at each cylinder. The resistive spark
plug cables are of nonmetallic construction. The
cables provide suppression of radio frequency emis-
sions from the ignition system.
DIAGNOSIS AND TESTING - SPARK PLUG
CABLES
Cable routing is important on certain engines. To
prevent possible ignition crossfire, be sure the cables
are clipped into the plastic routing looms. Try to pre-
vent any one cable from contacting another. Before
removing cables, note their original location and
routing. Never allow one cable to be twisted around
another.
Check the spark plug cable connections for good
contact at the coil(s), distributor cap towers, and
spark plugs. Terminals should be fully seated. The
insulators should be in good condition and should fit
tightly on the coil, distributor and spark plugs. Spark
plug cables with insulators that are cracked or torn
must be replaced.
Clean high voltage ignition cables with a cloth
moistened with a non-flammable solvent. Wipe the
cables dry. Check for brittle or cracked insulation.
On 3.9L/5.2L/5.9L engines, spark plug cable heat
shields are pressed into the cylinder head to sur-
round each spark plug cable boot and spark plug
(Fig. 37). These shields protect the spark plug boots
from damage (due to intense engine heat generated
by the exhaust manifolds) and should not be
removed. After the spark plug cable has been
installed, the lip of the cable boot should have a
small air gap to the top of the heat shield (Fig. 37).
TESTING
When testing secondary cables for damage with an
oscilloscope, follow the instructions of the equipment
manufacturer.
If an oscilloscope is not available, spark plug cables
may be tested as follows:
CAUTION: Do not leave any one spark plug cable
disconnected for longer than necessary during test-
ing. This may cause possible heat damage to the
catalytic converter. Total test time must not exceed
ten minutes.
Fig. 36 Heat ShieldsÐ3.9L/5.2L/5.9L Engines
1 - AIR GAP
2 - SPARK PLUG BOOT HEAT SHIELD
BR/BEIGNITION CONTROL 8I - 19
SPARK PLUG (Continued)

With the engine running, remove spark plug cable
from spark plug (one at a time) and hold next to a
good engine ground. If the cable and spark plug are
in good condition, the engine rpm should drop and
the engine will run poorly. If engine rpm does not
drop, the cable and/or spark plug may not be operat-
ing properly and should be replaced. Also check
engine cylinder compression.
With the engine not running, connect one end of a
test probe to a good ground. Start the engine and run
the other end of the test probe along the entire
length of all spark plug cables. If cables are cracked
or punctured, there will be a noticeable spark jump
from the damaged area to the test probe. The cable
running from the ignition coil to the distributor cap
can be checked in the same manner. Cracked, dam-
aged or faulty cables should be replaced with resis-
tance type cable. This can be identified by the words
ELECTRONIC SUPPRESSION printed on the cable
jacket.
Use an ohmmeter to test for open circuits, exces-
sive resistance or loose terminals. If equipped,
remove the distributor cap from the distributor.Do
not remove cables from cap.Remove cable from
spark plug. Connect ohmmeter to spark plug termi-
nal end of cable and to corresponding electrode in
distributor cap. Resistance should be 250 to 1000
Ohms per inch of cable. If not, remove cable from dis-
tributor cap tower and connect ohmmeter to the ter-
minal ends of cable. If resistance is not within
specifications as found in the SPARK PLUG CABLE
RESISTANCE chart, replace the cable. Test all spark
plug cables in this manner.
SPARK PLUG CABLE RESISTANCE
MINIMUM MAXIMUM
250 Ohms Per Inch 1000 Ohms Per Inch
3000 Ohms Per Foot 12,000 Ohms Per Foot
To test ignition coil-to-distributor cap cable, do not
remove the cable from the cap. Connect ohmmeter to
rotor button (center contact) of distributor cap and
terminal at ignition coil end of cable. If resistance is
not within specifications as found in the Spark Plug
Cable Resistance chart, remove the cable from the
distributor cap. Connect the ohmmeter to the termi-
nal ends of the cable. If resistance is not within spec-
ifications as found in the Spark Plug Cable
Resistance chart, replace the cable. Inspect the igni-
tion coil tower for cracks, burns or corrosion.
REMOVAL
CAUTION: When disconnecting a high voltage cable
from a spark plug or from the distributor cap, twist
the rubber boot slightly (1/2 turn) to break it loose
(Fig. 38). Grasp the boot (not the cable) and pull it
off with a steady, even force.
INSTALLATION
Install cables into the proper engine cylinder firing
order (Fig. 39), (Fig. 40) or (Fig. 41).
When replacing the spark plug and coil cables,
route the cables correctly and secure in the proper
retainers. Failure to route the cables properly can
cause the radio to reproduce ignition noise. It could
also cause cross ignition of the plugs or short circuit
the cables to ground.
Fig. 37 Heat ShieldsÐ3.9L/5.2L/5.9L Engines
1 - AIR GAP
2 - SPARK PLUG BOOT HEAT SHIELD
Fig. 38 Cable Removal
1 - SPARK PLUG CABLE AND BOOT
2 - SPARK PLUG BOOT PULLER
3 - TWIST AND PULL
4 - SPARK PLUG
8I - 20 IGNITION CONTROLBR/BE
SPARK PLUG CABLE (Continued)

When installing new cables, make sure a positive
connection is made. A snap should be felt when a
good connection is made between the plug cable and
the distributor cap tower.
Fig. 39 Engine Firing OrderÐ3.9L V-6 Engine
Fig. 40 Engine Firing OrderÐ5.2L/5.9L V-8 Engines
Fig. 41 Spark Plug Cable OrderÐ8.0L V-10 Engine
BR/BEIGNITION CONTROL 8I - 21
SPARK PLUG CABLE (Continued)

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 (st-run) fuse in the JB on a fused igni-
tion switch output (st-run) circuit. This arrangement
allows the EMIC to provide some features regardless
of the ignition switch position, while other features
will operate only with the ignition switch in the Start
or On positions. The EMIC circuitry is grounded
through two separate ground circuits located in one
of the two instrument cluster connectors and take
outs of the instrument panel wire harness. One
ground circuit receives ground through a take out
with an eyelet terminal connector of the instrument
panel wire harness that is secured by a nut to a
ground stud located on the left instrument panel end
bracket, while the other ground circuit receives
ground through a take out with an eyelet terminal
connector of the instrument panel wire harness that
is secured by a nut to a ground stud located on the
back of the instrument panel armature above the
inboard side of the instrument panel steering column
opening.
The EMIC also has a self-diagnostic actuator test
capability, which will test each of the CCD bus mes-
sage-controlled functions of the cluster by lighting
the appropriate indicators and positioning the gauge
needles at several predetermined locations on the
gauge faces in a prescribed sequence. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). See the owner's manual in the
vehicle glove box for more information on the fea-
tures, 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 supplied to any
gauges, and the EMIC circuitry is programmed 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 condition unless the
ignition switch is in the On or Start positions. All of
the EMIC gauges, except the odometer, are air core
magnetic units. Two fixed electromagnetic coils are
located within each gauge. These coils are wrapped
at right angles to each other around a movable per-
manent 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 fieldstrength. 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 mes-
sages received over the CCD 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 CCD data bus and
the data bus message inputs to the EMIC that con-
trol each gauge require the use of a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
Specific operation details for each gauge may be
found elsewhere in this service manual.
VACUUM-FLUORESCENT DISPLAY
The Vacuum-Fluorescent Display (VFD) module is
soldered to the EMIC circuit board. The display is
active with the ignition switch in the On or Start
positions, and inactive when the ignition switch is in
any other position. The VFD has several display
capabilities including odometer, trip odometer, and
an amber ªCRUISEº indication whenever the
optional speed control system is turned On. The
cruise indicator function of the VFD is automatically
enabled or disabled by the EMIC circuitry based
upon whether the vehicle is equipped with the speed
control option. An odometer/trip odometer switch on
the EMIC circuit board is used to control several of
the display modes. This switch is actuated manually
by depressing the odometer/trip odometer switch
knob that extends through the lower edge of the clus-
ter lens, just right of center. Actuating this switch
momentarily with the ignition switch in the On posi-
tion will toggle the VFD between the odometer and
trip odometer modes. The word ªTRIPº will also
appear in blue-green text when the VFD trip odome-
ter mode is active. Depressing the switch button for
about two seconds while the VFD is in the trip odom-
eter mode will reset the trip odometer value to zero.
Holding this switch depressed while turning the igni-
tion switch from the Off position to the On position
will activate the EMIC self-diagnostic actuator test.
The EMIC will automatically flash the odometer or
trip odometer information on and off if there is a loss
of CCD data bus communication. The VFD will also
display various information used in several diagnos-
tic procedures. Refer to the appropriate diagnostic
information for additional details on this VFD func-
tion.
8J - 4 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

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 CCD data bus and
the data bus message inputs to the EMIC that con-
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 require
the 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.
BR/BEINSTRUMENT CLUSTER 8J - 5
INSTRUMENT CLUSTER (Continued)

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
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.
8J - 6 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

(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.
(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 gauge
needles 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.
BR/BEINSTRUMENT CLUSTER 8J - 7
INSTRUMENT CLUSTER (Continued)

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.
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. Remove the instrument cluster from the
instrument panel. Move the CTM away from its
mounting bracket far enough to access the instru-
ment panel wire harness connector(s) for the CTM.
Disconnect the instrument panel wire harness con-
nector (Connector C1) from the CTM connector recep-
tacle.
(2) Check for continuity between the tone request
circuit cavity of the instrument panel wire harness
connector (Connector C2) for the instrument cluster
and a good ground. There should be no continuity. If
OK, go to Step 3. If not OK, repair the shorted tone
request circuit between the instrument cluster and
the CTM as required.
(3) Check for continuity between the tone request
circuit cavities of the instrument panel wire harnessconnector (Connector C2) for the instrument cluster
and the instrument panel wire harness connector
(Connector C1) for the CTM. There should be conti-
nuity. If OK, replace the faulty instrument cluster. If
not OK, repair the open tone request circuit between
the instrument cluster and the CTM as required.
CLUSTER ILLUMINATION DIAGNOSIS
The diagnosis found here addresses an inoperative
instrument cluster illumination lamp condition. If
the problem being diagnosed is a single inoperative
illumination lamp, be certain that the bulb and bulb
holder unit are properly installed in the instrument
cluster electronic circuit board. If no installation
problems are found replace the faulty bulb and bulb
holder unit. If all of the cluster illumination lamps
are inoperative and the problem being diagnosed
includes inoperative exterior lighting controlled by
the headlamp switch, that system needs to be
repaired first. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/HEADLAMP - DIAGNOSIS
AND TESTING). If no exterior lighting system prob-
lems are found, the following procedure will help
locate a short or open in the cluster illumination
lamp circuit. If the problem being diagnosed involves
a lack of dimming control for the odometer/trip odom-
eter Vacuum Fluorescent Display (VFD), but all of
the other cluster illumination lamps can be dimmed,
test and repair the day brightness circuit between
the instrument cluster and the headlamp switch as
required. Refer to the appropriate wiring informa-
tion. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, 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) Check the instrument panel dimmer fuse (Fuse
5 - 5 ampere) in the Junction Block (JB). If OK, go to
Step 2. If not OK, repair the shorted circuit or com-
ponent as required and replace the faulty fuse.
BR/BEINSTRUMENT CLUSTER 8J - 9
INSTRUMENT CLUSTER (Continued)