1998 DODGE RAM 1500 lighting

proper lamp-on or lamp-off messages to the instru-
ment cluster. If the PCM sends a lamp-on message
after the bulb test, it indicates that the PCM has
detected a system malfunction and/or that the ETC
system is inoperative. The PCM will store a Diagnos-
tic Trouble Code (DTC) for any malfunction it
detects. Each time the ETC indicator fails to illumi-
nate due to an open or short in the cluster ETC indi-
cator circuit, the cluster sends a message notifying
the PCM of the condition, the instrument cluster and
the PCM will each store a DTC. For proper diagnosis
of the ETC system, the PCM, the PCI data bus, or
the electronic message inputs to the instrument clus-
ter that control the ETC indicator, a DRBIIItscan
tool is required. Refer to the appropriate diagnostic
information.
FUEL GAUGE
DESCRIPTION
A fuel gauge is standard equipment on all instru-
ment clusters (Fig. 17). The fuel gauge is located in
the lower left quadrant of the instrument cluster,
below the voltage gauge. The fuel gauge consists of a
movable gauge needle or pointer controlled by the
instrument cluster circuitry and a fixed 90 degree
scale on the cluster overlay that reads left-to-right
from ªEº (or Empty) to ªFº (or Full). An International
Control and Display Symbol icon for ªFuelº is located
on the cluster overlay, directly below the right end of
the gauge scale. An arrowhead pointed to the left
side of the vehicle is imprinted on the cluster overlay
next to the ªFuelº icon in the fuel gauge to provide
the driver with a reminder as to the location of the
fuel filler access. On vehicles equipped with a diesel
engine, text that specifies ªDIESEL ONLYº is located
across the fuel gauge below the gauge scale, but
above the hub of the gauge needle. The fuel gauge
graphics are black against a white 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 black graphics appear blue and the red
graphics still 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 cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) on vehicles
equipped with a gasoline engine, or from the Engine
Control Module (ECM) on vehicles equipped with a
diesel engine over the Programmable Communica-
tions Interface (PCI) data bus. The fuel gauge is an
air core magnetic unit that receives battery current
on the instrument cluster electronic circuit board
through the fused ignition switch output (run-start)
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 or ECM
indicating the percent tank full, the cluster program-
ming applies an algorithm to calculate the proper
gauge needle position, then moves the gauge needle
to the proper relative position on the gauge scale.
The algorithm is used to dampen gauge needle move-
ment against the negative effect that fuel sloshing
within the fuel tank can have on accurate inputs
from the fuel tank sending unit to the PCM or ECM.
²Less Than Twenty Percent Tank Full Mes-
sage- Each time the cluster receives messages from
the PCM or ECM indicating the percent tank full is
about twenty percent or less for ten consecutive sec-
onds and the vehicle speed is zero, or for sixty con-
secutive seconds and the vehicle speed is greater
than zero, the gauge needle is moved to the one-
eighth graduation or below on the gauge scale, the
low fuel indicator is illuminated, and a single chime
tone is sounded. The low fuel indicator remains illu-
minated until the cluster receives messages from the
PCM or ECM indicating that the percent tank full is
greater than about twenty percent for ten consecu-
tive seconds and the vehicle speed is zero, or for sixty
consecutive 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 or ECM.
²Less Than Empty Percent Tank Full Mes-
sage- Each time the cluster receives a message from
Fig. 17 Fuel Gauge Icon
8J - 26 INSTRUMENT CLUSTERDR
ETC INDICATOR (Continued)

the PCM or ECM indicating the percent tank full is
less than empty, the gauge needle is moved to the far
left 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 or
ECM is a short circuit.
²More Than Full Percent Tank Full Message
- Each time the cluster receives a message from the
PCM or ECM indicating the percent tank full is more
than full, the gauge needle is moved to the far left
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 or
ECM is an open circuit.
²Communication Error- If the cluster fails to
receive a percent tank full message, it will hold the
gauge needle at the last indication about five seconds
or until the ignition switch is turned to the Off posi-
tion, whichever occurs first. After five seconds, the
cluster will move the gauge needle to the low end of
the gauge scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the fuel gauge needle will
be swept to several calibration points on the gauge
scale in a prescribed sequence in order to confirm the
functionality of the gauge and the cluster control cir-
cuitry.
On vehicles with a gasoline engine, the PCM con-
tinually monitors the fuel tank sending unit to deter-
mine the level of the fuel in the fuel tank. On
vehicles with a diesel engine, the ECM continually
monitors the fuel tank sending unit to determine the
level of the fuel in the fuel tank. The PCM or ECM
then sends the proper fuel level 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 ECM, the PCI data bus, or the elec-
tronic message inputs to the instrument cluster that
control the fuel gauge, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
GEAR SELECTOR INDICATOR
DESCRIPTION
An electronic automatic transmission gear selector
indicator is standard factory-installed equipment onthis model. The gear selector indicator information is
displayed in a Vacuum-Fluorescent Display (VFD)
unit. The VFD is soldered onto the cluster electronic
circuit board and is visible through a window with a
smoked clear lens located on the lower edge of the
speedometer gauge dial face of the cluster overlay.
The dark lens over the VFD prevents the indicator
from being clearly visible when it is not illuminated.
The gear selector indicator displays the following
characters from left to right: ªP,º ªR,º ªN,º ªD,º ª2,º
and ª1º (Fig. 18). Respectively, these characters rep-
resent the park, reverse, neutral, drive, second gear,
and first gear positions of the transmission gear
selector lever on the steering column. The VFD illu-
minates a rectangular box around the character that
represents the currently selected lever position.
The gear selector indicator characters and graphics
appear in the same blue-green color and at the same
lighting level as the odometer/trip odometer informa-
tion when illuminated by the instrument cluster elec-
tronic circuit board. During daylight hours (exterior
lamps Off) the gear selector indicator VFD is illumi-
nated at full brightness for clear visibility. At night
(exterior lamps are On) the VFD lighting level is
adjusted with the other cluster illumination lamps
using the panel lamps dimmer thumbwheel on the
headlamp switch. However, a ªParadeº mode position
of the panel lamps dimmer thumbwheel allows the
VFD to be illuminated at full brightness when the
vehicle is driven in daylight hours with the exterior
lamps turned On. The gear selector indicator VFD is
serviced as a unit with the instrument cluster.
OPERATION
The electronic gear selector indicator gives an indi-
cation to the vehicle operator of the transmission
gear that has been selected with the automatic trans-
mission gear selector lever. This indicator is con-
trolled by the instrument cluster circuit board based
upon cluster programming. The cluster circuitry
automatically configures itself for the proper trans-
mission and automatic transmission model based
upon the hard wired transmission range sensor mux
circuit input to the cluster. The gear selector indica-
tor information is displayed by a dedicated Vacuum
Fluorescent Display (VFD) unit on the instrument
cluster electronic circuit board, and the VFD will not
display the gear selector indicator information after
the ignition switch is turned to the Off position. The
instrument cluster circuitry configures the gear selec-
tor indicator VFD based upon the following inputs
from the transmission range sensor:
²Open Circuit- If the cluster is configured for
an automatic transmission and the transmission
range sensor mux circuit is open, the cluster circuitry
controls the gear selector indicator display based
Fig. 18 Gear Selector Indicator
DRINSTRUMENT CLUSTER 8J - 27
FUEL GAUGE (Continued)

tery saver) timed interval expires, whichever occurs
first.
²Actuator Test- Each time the cluster is put
through the actuator test, the high beam indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The instrument cluster continually monitors the
headlamp switch and the multi-function switch to
determine the proper headlamp low beam and high
beam control. The instrument cluster then sends the
proper low beam and high beam lamp-on and lamp-
off messages to the Front Control Module (FCM) over
the Programmable Communications Interface (PCI)
data bus and turns the high beam indicator on or off
accordingly. For further diagnosis of the high beam
indicator or the instrument cluster circuitry that con-
trols the indicator, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the headlamps, or
the headlamp switch and multi-function switch
inputs to the instrument cluster that control the high
beam indicator, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
LAMP OUT INDICATOR
DESCRIPTION
A lamp out indicator is standard equipment on all
instrument clusters (Fig. 20). The lamp out indicator
consists of the words ªLAMP OUTº, which appear in
the lower portion of the odometer/trip odometer Vac-
uum-Fluorescent Display (VFD) unit. The VFD is sol-
dered onto the cluster electronic circuit board and is
visible through a window with a smoked clear lens
located on the lower edge of the tachometer gauge
dial face of the cluster overlay. The dark lens over
the VFD prevents the indicator from being clearly
visible when it is not illuminated. The words ªLAMP
OUTº appear in an amber color and at the same
lighting level as the odometer/trip odometer informa-
tion when they are illuminated by the instrument
cluster electronic circuit board. The lamp out indica-
tor is serviced as a unit with the VFD in the instru-
ment cluster.
OPERATION
The lamp out indicator gives an indication to the
vehicle operator when an exterior lamp has failed.
This indicator is controlled by the instrument clustercircuit board based upon cluster programming and
electronic messages received by the cluster from the
Front Control Module (FCM) over the Programmable
Communications Interface (PCI) data bus. The lamp
out indicator is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the indicator will always be off when the ignition
switch is in any position except On or Start. The
indicator only illuminates when it is switched to
ground by the instrument cluster circuitry. The
instrument cluster will turn on the lamp out indica-
tor for the following reasons:
²Lamp Out Indicator Lamp-On Message-
Each time the cluster receives a lamp out indicator
lamp-on message from the FCM indicating that an
inoperative headlamp (low or high beam), turn signal
lamp, or brake lamp (excluding Center High
Mounted Stop Lamp [CHMSL]) circuit has been
detected, the lamp out indicator is illuminated. The
indicator remains illuminated until the cluster
receives a lamp out indicator lamp-off message from
the FCM 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 lamp out indicator will
be turned on, then off again during the VFD portion
of the test to confirm the functionality of the VFD
and the cluster control circuitry.
The FCM monitors each of the headlamp, turn sig-
nal lamp, and brake lamp (except CHMSL) circuits to
determine the condition of these exterior lamps. The
FCM then sends the proper lamp out indicator
lamp-on and lamp-off messages to the instrument
cluster. For further diagnosis of the lamp out indica-
tor or the instrument cluster circuitry that controls
the indicator, (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the exterior lighting system
circuits, the FCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the lamp out indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
Fig. 20 Lamp Out Indicator
DRINSTRUMENT CLUSTER 8J - 29
HIGH BEAM INDICATOR (Continued)

ODOMETER
DESCRIPTION
An odometer and trip odometer are standard
equipment in all instrument clusters (Fig. 23). The
odometer, trip odometer, and engine hours informa-
tion are displayed in a common electronic, blue-green
Vacuum-Fluorescent Display (VFD). The VFD is sol-
dered onto the cluster electronic circuit board and is
visible through a window with a smoked clear lens
located on the lower edge of the tachometer gauge
dial face of the cluster overlay. The dark lens over
the VFD prevents it from being clearly visible when
it is not illuminated. However, the odometer, trip
odometer, and engine hours information are not dis-
played simultaneously. The trip odometer reset
switch on the instrument cluster circuit board toggles
the display between odometer and trip odometer
modes by depressing the odometer/trip odometer
switch button that extends through the lower edge of
the cluster lens, just left of the odometer VFD. When
the trip odometer information is displayed, the word
ªTRIPº is also illuminated in the upper right corner
of the VFD in a blue-green color and at the same
lighting level as the trip odometer information. The
engine hours information replaces the selected odom-
eter or trip odometer information whenever the igni-
tion switch is in the On position and the engine is
not running.
The odometer, trip odometer, and engine hours
information is stored in the instrument cluster mem-
ory. This information can be increased when the
proper inputs are provided to the instrument cluster,
but the information cannot be decreased. The odom-
eter can display values up to 999,999 kilometers
(999,999 miles). The odometer latches at these val-
ues, and will not roll over to zero. The trip odometer
can display values up to 9,999.9 kilometers (9,999.9
miles) before it rolls over to zero. The odometer dis-
play does not have a decimal point and will not show
values less than a full unit (kilometer or mile), while
the trip odometer display does have a decimal point
and will show tenths of a unit (kilometer or mile).
The unit of measure (kilometers or miles) for the
odometer and trip odometer display is not shown in
the VFD. The unit of measure for the instrument
cluster odometer/trip odometer is selected at the time
that it is manufactured, and cannot be changed.
Engine hours are displayed in the format, ªhr9999º.The cluster will accumulate values up to 9,999 hours
before the display rolls over to zero.
The odometer has a ªRental Carº mode, which will
illuminate the odometer information in the VFD
whenever the driver side front door is opened with
the ignition switch in the Off or Accessory positions.
During daylight hours (exterior lamps are Off) the
VFD is illuminated at full brightness for clear visibil-
ity. At night (exterior lamps are On) the VFD lighting
level is adjusted with the other cluster illumination
lamps using the panel lamps dimmer thumbwheel on
the headlamp switch. However, a ªParadeº mode
position of the panel lamps dimmer thumbwheel
allows the VFD to be illuminated at full brightness if
the exterior lamps are turned On during daylight
hours.
The VFD, the trip odometer switch, and the trip
odometer switch button are serviced as a unit with
the instrument cluster.
OPERATION
The odometer and trip odometer give an indication
to the vehicle operator of the distance the vehicle has
traveled. The engine hours give an indication of the
cumulative engine-on time. This indicator is con-
trolled by the instrument cluster circuitry based
upon cluster programming and electronic messages
received by the cluster from the Powertrain Control
Module (PCM) over the Programmable Communica-
tions Interface (PCI) data bus. The odometer, trip
odometer and engine hours information is displayed
by the instrument cluster Vacuum Fluorescent Dis-
play (VFD). The VFD will display the odometer infor-
mation whenever any door is opened with the
ignition switch in the Off or Accessory positions, and
will display the last previously selected odometer or
trip odometer information when the ignition switch is
turned to the On or Start positions. The instrument
cluster circuitry controls the VFD and provides the
following features:
²Odometer/Trip Odometer Display Toggling-
Actuating the trip odometer reset switch button
momentarily with the VFD illuminated will toggle
the display between the odometer and trip odometer
information. Each time the VFD is illuminated with
the ignition switch in the On or Start positions, the
display will automatically return to the last mode
previously selected (odometer or trip odometer).
²Engine Hours Display Toggling- When the
trip odometer reset switch button is pressed and held
for longer than about six seconds with the ignition
switch in the On position and the engine speed mes-
sage from the PCM is zero, the trip odometer infor-
mation will be momentarily displayed, then the
engine hours information will be displayed. The VFD
must be displaying the odometer information when
Fig. 23 Odometer Display
8J - 32 INSTRUMENT CLUSTERDR

the trip odometer reset switch button is pressed in
order to toggle to the engine hours display. The
engine hours will remain displayed for about thirty
seconds, until the engine speed message is greater
than zero, or until the ignition switch is turned to
the Off position, whichever occurs first.
²Trip Odometer Reset- When the trip odome-
ter reset switch button is pressed and held for longer
than about two seconds with the ignition switch in
the On or Start positions, the trip odometer will be
reset to 0.0 kilometers (miles). The VFD must be dis-
playing the trip odometer information in order for
the trip odometer information to be reset.
²Communication Error- If the cluster fails to
receive a distance message during normal operation,
it will hold and display the last data received until
the ignition switch is turned to the Off position. If
the cluster does not receive a distance message
within one second after the ignition switch is turned
to the On position, it will display the last distance
message stored in the cluster memory. If the cluster
is unable to display distance information due to an
error internal to the cluster, the VFD display will be
dashes.
²Actuator Test- Each time the cluster is put
through the actuator test, the odometer VFD will dis-
play all of its segments simultaneously during the
VFD portion of the test to confirm the functionality
of each of the VFD segments and the cluster control
circuitry.
The PCM continually monitors the vehicle speed
pulse information received from the vehicle speed
sensor and engine speed pulse information received
from the crankshaft position sensor, then sends the
proper distance and engine speed messages to the
instrument cluster. For further diagnosis of the
odometer/trip odometer or the instrument cluster cir-
cuitry that controls these functions, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). For proper diagnosis of the
vehicle speed sensor, the crankshaft position sensor,
the PCM, the PCI data bus, or the electronic message
inputs to the instrument cluster that control the
odometer/trip odometer, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
OIL PRESSURE GAUGE
DESCRIPTION
An oil pressure gauge is standard equipment on all
instrument clusters. The oil pressure gauge is locatedin the upper right quadrant of the instrument clus-
ter, above the coolant temperature gauge. The oil
pressure gauge consists of a movable gauge needle or
pointer controlled by the instrument cluster circuitry
and a fixed 90 degree scale on the cluster overlay
that reads left-to-right from ªLº (or Low) to ªHº (or
High) for gasoline engines. On vehicles with a diesel
engine the scale reads from ª0º kPa to ª760º kPa in
markets where a metric instrument cluster is speci-
fied, or from ª0º psi to ª110º psi in all other markets.
An International Control and Display Symbol icon for
ªEngine Oilº is located on the cluster overlay, directly
below the left end of the gauge scale (Fig. 24). The oil
pressure gauge graphics are black against a white
field except for two red graduations at the low end of
the gauge scale, making them clearly visible within
the instrument cluster in daylight. When illuminated
from behind by the panel lamps dimmer controlled
cluster illumination lighting with the exterior lamps
turned On, the black graphics appear blue and the
red graphics still appear red. The orange gauge nee-
dle is internally illuminated. Gauge illumination is
provided by replaceable incandescent bulb and bulb
holder units located on the instrument cluster elec-
tronic circuit board. The oil pressure gauge is ser-
viced as a unit with the instrument cluster.
OPERATION
The oil pressure gauge gives an indication to the
vehicle operator of the engine oil pressure. This
gauge is controlled by the instrument cluster circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) on vehicles with a
gasoline engine, or from the Engine Control Module
(ECM) on vehicles equipped with a diesel engine over
the Programmable Communications Interface (PCI)
data bus. The oil pressure gauge is an air core mag-
netic unit that receives battery current on the instru-
ment cluster electronic circuit board through the
fused ignition switch output (run-start) circuit when-
ever the ignition switch is in the On or Start posi-
tions. The cluster is programmed to move the gauge
needle back to the low end of the scale after the igni-
tion switch is turned to the Off position. The instru-
ment cluster circuitry controls the gauge needle
position and provides the following features:
²Engine Oil Pressure Message- The instru-
ment cluster circuitry restricts the oil pressure gauge
needle operation in order to provide readings that
are consistent with customer expectations. Each time
the cluster receives a message from the PCM or ECM
indicating the engine oil pressure is above about 41
kPa (6 psi) the cluster holds the gauge needle at a
point near the middle increment within the normal
range on the gauge scale.
Fig. 24 Engine Oil Icon
DRINSTRUMENT CLUSTER 8J - 33
ODOMETER (Continued)

reminder function, each time the cluster detects an
open circuit on the seat belt indicator driver circuit
(seatbelt switch open = seatbelt unbuckled) with the
ignition switch in the Start or On positions, the indi-
cator will be illuminated. In addition, if the driver
side front seat belt remains unbuckled about sixty
seconds after the conclusion of the seatbelt reminder
function with the vehicle speed greater than about 13
kilometers-per-hour (8 miles-per-hour), the seatbelt
indicator will begin to cycle between flashing on and
off for five seconds, then lighting solid for three sec-
onds. The seatbelt indicator will continue to cycle
between flashing and solid illumination for twelve
complete cycles, until the seat belt indicator driver
input to the cluster is closed to ground (seatbelt
switch closed = seatbelt buckled), or until the igni-
tion switch is turned to the Off position, whichever
occurs first.
²Driver Side Front Seatbelt Not Buckled -
Beltminder Inactive- Following the seatbelt
reminder function, each time the cluster detects an
open circuit on the seat belt indicator driver circuit
(seatbelt switch open = seatbelt unbuckled) with the
ignition switch in the Start or On positions, the indi-
cator will be illuminated. The seatbelt indicator
remains illuminated until the seat belt indicator
driver input to the cluster is closed to ground (seat-
belt switch closed = seatbelt buckled), or until the
ignition switch is turned to the Off position, which-
ever occurs first.
²Airbag Indicator Backup- If the instrument
cluster detects a fault in the airbag indicator circuit
it will send a message indicating the fault to the Air-
bag Control Module (ACM), store a Diagnostic Trou-
ble Code (DTC) in the cluster memory, then flash the
seatbelt indicator on and off. The cluster will con-
tinue to flash the seatbelt indicator until the airbag
indicator circuit fault is resolved, 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 seatbelt indicator will
be turned on, then off again during the bulb check
portion of the test to confirm the functionality of the
LED and the cluster control circuitry.
The seatbelt switch is connected in series between
ground and the seat belt indicator driver input to the
instrument cluster. The seatbelt switch input to the
instrument cluster circuitry may be diagnosed using
conventional diagnostic tools and methods. For fur-
ther diagnosis of the seatbelt indicator or the instru-
ment cluster circuitry that controls the LED, (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DIAGNOSIS AND TESTING).STANDARD PROCEDURE - ENHANCED
SEATBELT REMINDER PROGRAMMING
The seatbelt indicator also includes a programma-
ble enhanced seatbelt reminder or ªbeltminderº fea-
ture that is enabled when the vehicle is shipped from
the factory. This beltminder feature provides
extended and modified visual seatbelt indicator and
audible chime warning responses to an unbuckled
driver side front seat belt. The beltminder feature
may be disabled or enabled by the customer using
the programming sequence that follows, or by the
dealer using a DRBIIItscan tool. The following
sequence of events must occur within sixty (60) sec-
onds of the ignition switch being placed in the On
position in order for the programming to be com-
pleted successfully.
(1) With the ignition switch in any position except
On or Start, buckle the driver side front seat belt.
(2) Turn the ignition switch to the On position and
wait for the seatbelt indicator reminder function to
conclude (about six seconds).
(3) Unbuckle and buckle the driver side front seat
belt three or more times, ending with the belt buck-
led.
(4) Turn the ignition switch to any position except
On or Start to toggle the beltminder feature from its
current setting (from active to inactive, or from inac-
tive to active). A single chime tone will provide an
audible confirmation that the programming sequence
has been successfully completed.
SECURITY INDICATOR
DESCRIPTION
A security indicator is standard equipment on all
instrument clusters (Fig. 26). However, on vehicles
not equipped with the optional Vehicle Theft Security
System (VTSS), this indicator is electronically dis-
abled. The security indicator is located in the lower
right quadrant of the instrument cluster, between the
speedometer and the coolant temperature gauge. The
security indicator consists of a small round cutout in
the opaque layer of the instrument cluster overlay.
The dark outer layer of the overlay prevents the indi-
cator from being clearly visible when it is not illumi-
nated. A red Light Emitting Diode (LED) behind the
cutout in the opaque layer of the overlay causes the
indicator to appear in red through the translucent
outer layer of the overlay when it is illuminated from
Fig. 26 Security Indicator
DRINSTRUMENT CLUSTER 8J - 35
SEATBELT INDICATOR (Continued)

appears in the lower portion of the odometer/trip
odometer Vacuum Fluorescent Display (VFD) unit.
The VFD is soldered onto the cluster electronic cir-
cuit board and is visible through a window with a
smoked clear lens located on the lower edge of the
tachometer gauge dial face of the cluster overlay. The
dark lens over the VFD prevents the indicator from
being clearly visible when it is not illuminated. The
text ªSERV 4WDº appears in an amber color and at
the same lighting level as the odometer/trip odometer
information when they are illuminated by the instru-
ment cluster electronic circuit board. The service
4WD indicator is serviced as a unit with the VFD in
the instrument cluster.
OPERATION
The service 4WD indicator gives an indication to
the vehicle operator when the Transfer Case Control
Module (TCCM) has recorded a Diagnostic Trouble
Code (DTC) for an electronic transfer case circuit or
component malfunction. This indicator is controlled
by a transistor on the instrument cluster circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
TCCM over the Programmable Communications
Interface (PCI) data bus. The service 4WD indicator
is completely controlled by the instrument cluster
logic circuit, and that logic will only allow this indi-
cator to operate when the instrument cluster receives
a battery current input on the fused ignition switch
output (run-start) circuit. Therefore, the indicator
will always be off when the ignition switch is in any
position except On or Start. The indicator only illu-
minates when it is switched to ground by the instru-
ment cluster circuitry. The instrument cluster will
turn on the service 4WD indicator for the following
reasons:
²Service 4WD Lamp-On Message- Each time
the cluster receives a service 4WD lamp-on message
from the TCCM, the indicator will be illuminated.
The indicator remains illuminated until the cluster
receives a service 4WD lamp-off message from the
TCCM, or until the ignition switch is turned to the
Off position, whichever occurs first.
²Communication Error- If the cluster receives
no messages from the TCCM for five seconds, the
service 4WD indicator is illuminated by the instru-
ment cluster to indicate a loss of TCCM communica-
tion. The indicator remains controlled and
illuminated by the cluster until a valid message is
received from the TCCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the service 4WD indicator
will be turned on, then off again during the VFD por-
tion of the test to confirm the functionality of the
VFD and the cluster control circuitry.The TCCM continually monitors the electronic
transfer case switch and circuits to determine the
condition of the system. The TCCM then sends the
proper lamp-on or lamp-off messages to the instru-
ment cluster. For further diagnosis of the service
4WD indicator or the instrument cluster circuitry
that controls the VFD, (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the TCCM, the
PCI data bus, or the electronic message inputs to the
instrument cluster that control the service 4WD indi-
cator, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
SPEEDOMETER
DESCRIPTION
A speedometer is standard equipment on all instru-
ment clusters. The speedometer is located next to the
tachometer, just to the right of center in the instru-
ment cluster. The speedometer consists of a movable
gauge needle or pointer controlled by the instrument
cluster circuitry and a fixed 210 degree primary scale
on the gauge dial face that reads left-to-right either
from ª0º to ª120º mph, or from ª0º to ª200º km/h,
depending upon the market for which the vehicle is
manufactured. Each version also has a secondary
inner scale on the gauge dial face that provides the
equivalent opposite units from the primary scale.
Text appearing on the cluster overlay just below the
hub of the speedometer needle abbreviates the unit
of measure for the primary scale (i.e.: MPH or km/h),
followed by the unit of measure for the secondary
scale (Fig. 28). The speedometer graphics are black
(primary scale) and blue (secondary scale) against a
white field, making them clearly visible within the
instrument cluster in daylight. When illuminated
from behind by the panel lamps dimmer controlled
cluster illumination lighting with the exterior lamps
turned On, the black graphics appear dark blue and
the blue graphics appear light blue. The orange
gauge needle is internally illuminated. Gauge illumi-
nation is provided by replaceable incandescent bulb
and bulb holder units located on the instrument clus-
ter electronic circuit board. The speedometer is ser-
viced as a unit with the instrument cluster.
OPERATION
The speedometer gives an indication to the vehicle
operator of the vehicle road speed. This gauge is con-
Fig. 28 Speedometer Text
DRINSTRUMENT CLUSTER 8J - 37
SERVICE 4WD INDICATOR (Continued)

trolled by the instrument cluster circuit board based
upon cluster programming and electronic messages
received by the cluster from the Powertrain Control
Module (PCM) over the Programmable Communica-
tions Interface (PCI) data bus. The speedometer is an
air core magnetic unit that receives battery current
on the instrument cluster electronic circuit board
through the fused ignition switch output (run-start)
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:
²Vehicle Speed Message- Each time the clus-
ter receives a vehicle speed message from the PCM it
will calculate the correct vehicle speed reading and
position the gauge needle at that relative speed posi-
tion on the gauge scale. The cluster will receive a
new vehicle speed message and reposition the gauge
pointer accordingly about every 88 milliseconds. The
gauge needle will continue to be positioned at the
actual vehicle speed position on the gauge scale until
the ignition switch is turned to the Off position.
²Communication Error- If the cluster fails to
receive a speedometer message, it will hold the gauge
needle at the last indication for about three seconds,
or until the ignition switch is turned to the Off posi-
tion, whichever occurs first. After three seconds, the
gauge needle will return to the left end of the gauge
scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the speedometer needle
will be swept to several calibration points on the
gauge scale in a prescribed sequence in order to con-
firm the functionality of the gauge and the cluster
control circuitry.
The PCM continually monitors the vehicle speed
sensor to determine the vehicle road speed. The PCM
then sends the proper vehicle speed messages to the
instrument cluster. For further diagnosis of the
speedometer or the instrument cluster circuitry that
controls the gauge, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND TEST-
ING). For proper diagnosis of the vehicle speed
sensor, the PCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the speedometer, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
TACHOMETER
DESCRIPTION
A tachometer is standard equipment on all instru-
ment clusters. The tachometer is located to the left ofthe speedometer, just to the left of center in the
instrument cluster. The tachometer consists of a
movable gauge needle or pointer controlled by the
instrument cluster circuitry and a fixed 210 degree
scale on the gauge dial face that reads left-to-right
from ª0º to ª7º for gasoline engines. On vehicles with
a diesel engine, the scale reads from ª0º to ª5º. The
text ªRPM X 1000º imprinted on the cluster overlay
directly below the hub of the tachometer needle iden-
tifies that each number on the tachometer scale is to
be multiplied by 1000 rpm (Fig. 29). The tachometer
graphics are black against a white field, making
them clearly visible within the instrument cluster in
daylight. When illuminated from behind by the panel
lamps dimmer controlled cluster illumination lighting
with the exterior lamps turned On, the black graph-
ics appear blue. The orange gauge needle is inter-
nally illuminated. Gauge illumination is provided by
replaceable incandescent bulb and bulb holder units
located on the instrument cluster electronic circuit
board. The tachometer is serviced as a unit with the
instrument cluster.
OPERATION
The tachometer gives an indication to the vehicle
operator of the engine speed. This gauge is controlled
by the instrument cluster circuit board based upon
cluster programming and electronic messages
received by the cluster from the Powertrain Control
Module (PCM) on vehicles with a gasoline engine, or
from the Engine Control Module (ECM) on vehicles
equipped with a diesel engine over the Programma-
ble Communications Interface (PCI) data bus. The
tachometer is an air core magnetic unit that receives
battery current on the instrument cluster electronic
circuit board through the fused ignition switch out-
put (run-start) circuit whenever the ignition switch is
in the On or Start positions. The cluster is pro-
grammed 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:
²Engine Speed Message- Each time the cluster
receives an engine speed message from the PCM or
ECM it will calculate the correct engine speed read-
ing and position the gauge needle at that relative
speed position on the gauge scale. The cluster will
receive a new engine speed message and reposition
the gauge pointer accordingly about every 88 milli-
seconds. The gauge needle will continually be reposi-
Fig. 29 Tachometer Text
8J - 38 INSTRUMENT CLUSTERDR
SPEEDOMETER (Continued)