1998 DODGE RAM 1500 ad blue

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)

cator is electronically disabled. The upshift indicator
consists of an upward pointed arrow icon, which
appears on the right side of the electronic gear selec-
tor indicator 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 icon appears in a blue-green color and at the
same lighting level as the odometer/trip odometer
information when it is illuminated by the instrument
cluster electronic circuit board. The upshift indicator
is serviced as a unit with the instrument cluster.
OPERATION
The upshift indicator gives an indication to the
vehicle operator when the manual transmission
should be shifted to the next highest gear in order to
achieve the best fuel economy. This indicator is con-
trolled 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
with a diesel engine over the Programmable Commu-
nications Interface (PCI) data bus. The upshift indi-
cator is completely controlled by the instrument
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 indi-
cator 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 upshift indicator for the following
reasons:
²Upshift Lamp-On Message- Each time the
cluster receives an upshift lamp-on message from the
PCM or ECM indicating the engine speed and load
conditions are right for a transmission upshift to
occur, the upshift indicator is illuminated. The indi-
cator remains illuminated until the cluster receives
an upshift lamp-off message from the PCM or ECM,
or until the ignition switch is turned to the Off posi-
tion, whichever occurs first. The PCM or ECM will
normally send an upshift lamp-off message three to
five seconds after a lamp-on message, if an upshift is
not performed. The indicator will then remain off
until the vehicle stops accelerating and is brought
back into the range of indicator operation, or until
the transmission is shifted into another gear.
²Actuator Test- Each time the cluster is put
through the actuator test, the upshift indicator willbe turned on, then off again during the VFD portion
of the test to confirm the functionality of the VFD
and the cluster control circuitry.
On vehicles with a gasoline engine, the PCM con-
tinually monitors the engine speed and load condi-
tions to determine the proper fuel and ignition
requirements. On vehicles with a diesel engine, the
ECM continually monitors the engine speed and load
conditions to determine the proper fuel requirements.
The PCM or ECM then sends the proper upshift indi-
cator lamp-on and lamp-off messages to the instru-
ment cluster. For further diagnosis of the upshift
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 PCM, the
ECM, the PCI data bus, or the electronic message
inputs to the instrument cluster that control the
upshift indicator, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
VOLTAGE GAUGE
DESCRIPTION
A voltage gauge is standard equipment on all
instrument clusters. The voltage gauge is located in
the upper left quadrant of the instrument cluster,
above the fuel gauge. The voltage 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 ª8º to ª18º volts. An International Control
and Display Symbol icon for ªBattery Charging Con-
ditionº is located on the cluster overlay, directly
below the right end of the gauge scale (Fig. 34). The
voltage gauge graphics are black against a white
field except for a single red graduation at each 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 voltage gauge is serviced as
a unit with the instrument cluster.
Fig. 34 Battery Charging Condition Icon
8J - 42 INSTRUMENT CLUSTERDR
UPSHIFT INDICATOR (Continued)

NAVIGATION/TELECOMMUNICATION
TABLE OF CONTENTS
page page
NAVIGATION/TELECOMMUNICATION
DESCRIPTION..........................1
OPERATION............................1HANDS FREE MODULE
REMOVAL.............................2
INSTALLATION..........................2
NAVIGATION/
TELECOMMUNICATION
DESCRIPTION
TELECOMMUNICATIONS
The hands-free cellular system on this vehicle uses
BluetoothŸ technology to provide wireless communi-
cation between the operator's compatible cellular
telephone and the vehicle's on-board receiver.
The system uses voice recognition technology to
control operation. The incoming voice is broadcast
through the vehicle's radio speakers, automatically
overriding any other audio signals on the front
speakers when the hands-free system is in use. A
microphone in the rearview mirror picks up vehicle
occupant's voices. If a call is in progress when the
ignition is switched off, the hands-free system will
continue to operate for up to 45 seconds as part of
the Accessory Relay Delay function. Thereafter, the
call can continue on the hand-held telephone.
The system will communicate with a telephone
that is anywhere within the vehicle. However, cover-
ing the hand held phone or the hands-free phone
module with a metal object may block the signal. The
system will recognize up to seven telephones, each of
which is given a spoken identification by the user
during the setup process. The system includes Span-
ish and French voice recognition in addition to
English.
Two buttons on the rearview mirror, identified with
ISO icons, control the system: A9phone9button turns
the system on and off; a9voice recognition9(or voice
command) button prompts the hands-free system to
listen for a voice command.
OPERATION
TELECOMMUNICATION
Two buttons on the rearview mirror, identified with
ISO icons, control the system: A9phone9button turns
the system on and off; a9voice recognition9(or voice
command) button prompts the hands-free system to
listen for a voice command. The system includes the
following features:
²Phone book - Stores telephone numbers for later
recall by name or other verbal identification, called a
voice tag, and memory location.
²Four memory locations - Home, Work, Cellular
and Pager. A maximum of 32 unique names or voice
tags may be stored at the same time, with a different
number in each of the four memory locations.
²Voice tag dialing - Dials the number associated
with a voice tag and memory location.
²Digit dialing - Dials the telephone number by
recognizing the names of the digits as they are spo-
ken.
²Receiving calls - A voice prompt notifies the user
of an incoming call. A voice response accepts or
rejects the call without manual intervention.
²Privacy Mode - Switches the call to the hand-
held telephone and the hands-free system and back
again using the ªvoice recognitionº (or ªvoice com-
mandº) button and a voice command, if desired.
DRNAVIGATION/TELECOMMUNICATION 8T - 1

TERMINOLOGY
This is a list of terms and definitions used in the
wiring diagrams.
LHD.................Left Hand Drive Vehicles
RHD ...............Right Hand Drive Vehicles
ATX . . Automatic Transmissions-Front Wheel Drive
MTX . . . Manual Transmissions-Front Wheel Drive
AT....Automatic Transmissions-Rear Wheel Drive
MT .....Manual Transmissions-Rear Wheel Drive
SOHC...........Single Over Head Cam Engine
DOHC..........Double Over Head Cam Engine
Export . . Vehicles Built For Sale In Markets Other
Than North America
Except Export.... Vehicles Built For Sale In North
America
DESCRIPTION - CIRCUIT INFORMATION
Each wire shown in the diagrams contains a code
which identifies the main circuit, part of the main
circuit, gage of wire, and color (Fig. 4).
WIRE COLOR CODE CHART
COLOR CODE COLOR
BL BLUE
BK BLACK
BR BROWN
DB DARK BLUE
DG DARK GREEN
GY GRAY
LB LIGHT BLUE
LG LIGHT GREEN
OR ORANGE
PK PINK
RD RED
TN TAN
VT VIOLET
WT WHITE
YL YELLOW
* WITH TRACER
Fig. 4 WIRE CODE IDENTIFICATION
1 - COLOR OF WIRE (LIGHT BLUE WITH YELLOW TRACER
2 - GAGE OF WIRE (18 GAGE)
3 - PART OF MAIN CIRCUIT (VARIES DEPENDING ON
EQUIPMENT)
4 - MAIN CIRCUIT IDENTIFICATION
DR8W-01 WIRING DIAGRAM INFORMATION 8W - 01 - 5
WIRING DIAGRAM INFORMATION (Continued)

ADJUSTABLE PEDAL SWITCH (EXCEPT MEMORY) - BLUE 6 WAY
CAV CIRCUIT FUNCTION
1 P206 18LG/LB ADJUSTABLE PEDALS MOTOR REVERSE
2 A72 18RD/OR ADJUSTABLE PEDAL RELAY OUTPUT
3- -
4 Z146 18BK GROUND
5 F504 20GY/PK FUSED IGNITION SWITCH OUTPUT (RUN)
6 P205 18LG/WT ADJUSTABLE PEDALS MOTOR FORWARD
AIRBAG CONTROL MODULE C1 - 24 WAY
CAV CIRCUIT FUNCTION
1- -
2- -
3 D25 20WT/VT PCI BUS
4- -
5 Z104 18BK/LG GROUND
6 G104 20VT/GY PASSENGER AIRBAG INDICATOR DRIVER
7 R104 20LB/LG PASSENGER AIRBAG MUX SWITCH RETURN
8 R106 20LG/LB PASSENGER AIRBAG MUX SWITCH SENSE
9- -
10 - -
11 - -
12 - -
13 - -
14 - -
15 - -
16 - -
17 R43 20LG/BR DRIVER SQUIB 1 LINE 1
18 R45 20LG/OR DRIVER SQUIB 1 LINE 2
19 R44 20LB/OR PASSENGER SQUIB 1 LINE 2
20 R42 20LB/BR PASSENGER SQUIB 1 LINE 1
21 R61 20LG/VT DRIVER SQUIB 2 LINE 1
22 R63 20LG/WT DRIVER SQUIB 2 LINE 2
23 R64 20LB/WT PASSENGER SQUIB 2 LINE 1
24 R62 20LB/VT PASSENGER SQUIB 2 LINE 2
8W - 80 - 8 8W-80 CONNECTOR PIN-OUTSDR

DRIVER DOOR MODULE C1 - BLUE 12 WAY
CAV CIRCUIT FUNCTION
1 Q612 14OR/DB RIGHT REAR WINDOW DRIVER (DOWN)
2 Q412 14OR/LB RIGHT REAR WINDOW DRIVER (UP)
3 Q16 14OR/TN MASTER WINDOW SWITCH RIGHT FRONT (UP)
4 Q411 14OR/WT LEFT REAR WINDOW DRIVER (UP)
5 Q11 14OR/LG LEFT FRONT WINDOW DRIVER (UP)
6 Q26 14OR/GY MASTER WINDOW SWITCH RIGHT FRONT (DOWN)
7 G161 20VT/DG DRIVER DOOR LOCK SWITCH MUX
8 Z421 14BK/BR GROUND
9 F30 14PK/YL FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
10 Q611 14OR/GY LEFT REAR WINDOW DRIVER (DOWN)
11 Z941 20BK GROUND
12 Q21 14OR/WT LEFT FRONT WINDOW DRIVER (DOWN)
DRIVER DOOR MODULE C2 - BLUE 8 WAY
CAV CIRCUIT FUNCTION
1 P71 18TN/DG LEFT MIRROR UP DRIVER
2 P195 18LG/YL LEFT MIRROR COMMON DRIVER (RIGHT/DOWN)
3 A930 18RD FUSED B(+)
4 P74 18TN/OR RIGHT MIRROR LEFT DRIVER
5 Z461 20BK/DG GROUND
6 P75 18TN/LG LEFT MIRROR LEFT DRIVER
7 P72 18TN/GY RIGHT MIRROR UP DRIVER
8 Q15 14OR/LB POWER WINDOW SWITCH FEED
EGR SOLENOID (4.7L/5.7L)-6WAY
CAV CIRCUIT FUNCTION
1 K34 18DB/LG EGR SENSOR SIGNAL
2 F856 20YL/PK 5 VOLT SUPPLY
3 K900 20DB/DG SENSOR GROUND
4 Z335 18BK/WT GROUND
5- -
6 K35 18DB/VT EGR SOLENOID CONTROL
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 57

HEADLAMP SWITCH - BLACK 8 WAY
CAV CIRCUIT FUNCTION
1- -
2- -
3 E19 20OR/BR PANEL LAMPS DIMMER SIGNAL
4 Z407 20BK/OR GROUND
5 L89 20WT/YL (FOG LAMPS) FOG LAMP RELAY OUTPUT
6 E2 20OR/BR PANEL LAMPS DIMMER SIGNAL
7 L115 20WT/YL HEADLAMP SWITCH RETURN
8 L116 20WT/LG HEADLAMP SWITCH SIGNAL
HEADLAMP-LEFT - BLUE 3 WAY
CAV CIRCUIT FUNCTION
A L43 18WT/DB LEFT LOW BEAM OUTPUT
B Z345 18BK/LB GROUND
C L33 18WT/LG LEFT HIGH BEAM OUTPUT
HEADLAMP-RIGHT - BLUE 3 WAY
CAV CIRCUIT FUNCTION
A L44 18WT/TN RIGHT LOW BEAM OUTPUT
B Z346 18BK/LG GROUND
C L34 18WT/GY RIGHT HIGH BEAM OUTPUT
HEATED SEAT CUSHION-DRIVER - BLUE 4 WAY
CAV CIRCUIT FUNCTION
1 P187 18LG/BR DRIVER SEAT TEMPERATURE SENSOR INPUT
2 Z939 20BK GROUND
3 P53 20LG/OR DRIVER SEAT TEMPERATURE 5 VOLT SUPPLY
4 P89 20LG/OR SEAT HEATER DRIVER
8W - 80 - 68 8W-80 CONNECTOR PIN-OUTSDR