1998 DODGE RAM 1500 instrument cluster

INLET AIR TEMPERATURE SENSOR-4WAY
CAV CIRCUIT FUNCTION
1 K690 18BR/YL (A/T) INLET AIR TEMPERATURE/PRESSURE RETURN
1 K690 18DG/YL (M/T) INLET AIR TEMPERATURE/PRESSURE RETURN
2 K615 18VT/WT (A/T) INLET AIR TEMPERATURE SENSE
2 K615 18BR/WT (M/T) INLET AIR TEMPERATURE SENSE
3 K668 18BR (A/T) SUPPLY VOLTAGE
3 K668 18LG (M/T) SUPPLY VOLTAGE
4 K616 18BR/YL INLET AIR PRESSURE SENSE
INPUT SPEED SENSOR (45RFE) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 T52 18DG/OR INPUT SPEED SENSOR SIGNAL
2 T13 18DG/VT SPEED SENSOR GROUND
INSTRUMENT CLUSTER C1 - WHITE 26 WAY
CAV CIRCUIT FUNCTION
1 P1 18TN/LG (SLT) DOOR UNLOCK DRIVER LEFT FRONT
2 A941 18RD FUSED B(+)
3 K32 18DB/YL BTSI SOLENOID CONTROL
4- -
5- -
6- -
7 E16 20OR/GY PANEL LAMPS DRIVER
8 E14 20OR/TN PANEL LAMPS DRIVER
9 E19 20OR/BR PANEL LAMPS DIMMER SIGNAL
10 P393 18LG (SLT) DOOR LOCK DRIVER LEFT DOORS
11 P392 18LG/DB (SLT) DOOR LOCK DRIVER RIGHT DOORS
12 - -
13 Z921 18BK GROUND
14 Z108 20BK/LG GROUND
15 M288 18YL/GY FUSED B(+)
16 P85 20LG/WT (SLT+) HEATED SEAT SWITCH SUPPLY
17 M228 18YL/LB (SLT) COURTESY LAMP DRIVER
18 L14 20WT/TN CARGO LAMP DRIVER
19 P301 20LG/OR (SLT+) PANEL LAMPS DRIVER
20 E11 20OR/DB (SLT) PANEL LAMPS DRIVER
21 M20 20YL/LB COURTESY LAMPS DRIVER
22 M22 20YL/OR COURTESY LAMPS DRIVER
23 P5 18TN/OR (SLT) DOOR UNLOCK DRIVER LEFT REAR
24 G778 18VT/LB (SLT) DOOR UNLOCK DRIVER RIGHT DOORS
25 A944 20RD FUSED B(+)
26 A944 20RD FUSED B(+)
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 71

INSTRUMENT CLUSTER C2 - GRAY 16 WAY
CAV CIRCUIT FUNCTION
1 G194 20VT/LG WASH/BEAM SELECT SWITCH SIGNAL
2 G160 20VT/LG (SLT)8PASSENGER DOOR LOCK SWITCH MUX
3 G161 20VT/DG (SLT) DRIVER DOOR LOCK SWITCH MUX
4 E2 20OR/BR PANEL LAMPS DIMMER SIGNAL
5 L116 20WT/LG HEADLAMP SWITCH SIGNAL
6- -
7 G163 20VT/LB (SLT) DRIVER CYLINDER LOCK SWITCH MUX
8 L12 20WT/OR TURN LAMPS SWITCH SIGNAL
9- -
10 W52 20BR/YL INTERMITTENT WIPER SWITCH SIGNAL
11 T117 20DG/YL TRANS RANGE SENSOR ELECTRONIC CLUSTER 5
VOLT SUPPLY
12 X20 20GY/WT (SLT PREMIUM RADIO) RADIO CONTROL MUX
13 - -
14 - -
15 - -
16 - -
INSTRUMENT CLUSTER C3 - GRAY 26 WAY
CAV CIRCUIT FUNCTION
1 G75 20VT DRIVER DOOR AJAR SWITCH SENSE
2 G77 20VT/GY LEFT REAR DOOR AJAR SWITCH SENSE
3 G76 20VT/YL RIGHT REAR DOOR AJAR SWITCH SENSE
4 G74 20VT/WT PASSENGER DOOR AJAR SWITCH SENSE
5- -
6- -
7 K77 18BR/WT TRANSFER CASE POSITION SENSOR INPUT
8 L900 20WT/YL WIPER/TURN/BEAM SELECT SWITCH RETURN
9 L115 20WT/YL HEADLAMP SWITCH RETURN
10 T917 20YL/TN TRANS RANGE SENSOR ELECTRONIC CLUSTER MUX
11 - -
12 - -
13 Z18 20BK/LB GROUND
14 X3 20DG/VT HORN SWITCH SENSE
15 L50 18WT/TN BRAKE LAMP SWITCH OUTPUT
16 G15 20VT/TN KEY IN IGNITION SWITCH SENSE
17 - -
18 - -
19 D25 20WT/VT PCI BUS
20 G10 20VT/LG SEAT BELT SWITCH SENSE
21 - -
22 B25 20DG/WT PARK BRAKE SWITCH SENSE
23 F983 20PK/YL FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
24 F1 16PK/WT FUSED IGNITION SWITCH OUTPUT (OFF-RUN-START)
25 F21 20PK/DG FUSED IGNITION SWITCH OUTPUT (RUN-START)
26 A114 18GY/RD FUSED B(+)
8W - 80 - 72 8W-80 CONNECTOR PIN-OUTSDR

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Glove Box Lamp and Switch BK At Glove Box 35, 39
Governor Pressure Sensor BK Left Rear of Transmission N/S
Hands Free Module Right Instrument Panel 39
Headlamp Switch BK Left Side of Instrument Panel 32, 35, 38
Headlamp-Left BL At Headlamp 23, 28, 29
Headlamp-Right BL At Headlamp 1, 21, 26
Heated Seat Cushion - Driver BL Under Driver Seat N/S
Heated Seat Cushion - Passenger BL Under Passenger Seat N/S
Heated Seat Switch-Driver RD Center of Instrument Panel 33, 35, 36
Heated Seat Switch-Passenger BL Center of Instrument Panel 33, 35, 36
Horn Switch WT In Steering Wheel N/S
Horn-High Note BK Left Front Fender 23, 28, 29
Horn-Low Note BK Left Front Fender 23, 29
Idle Air Control Motor BK On Throttle Body 6
Ignition Coil GY Left Rear of Engine N/S
Ignition Switch BK Steering Column 31
Inlet Air Temperature/Pressure
SensorBK Right Side Engine 10
Input Speed Sensor BK At Transmission 15, 16
Instrument Cluster C1 GY Rear of Instrument Cluster 35
Instrument Cluster C2 GY Rear of Instrument Cluster 35
Instrument Cluster C3 WT Rear of Instrument Cluster 35
Intake Air Heater Relay Right Engine Compartment 2
Intake Air Temperature/Manifold
Absolute Pressure Sensor (Diesel)BK Left rear Engine N/S
Intake Air Temperature Sensor BK On Intake Manifold 5
Integrated Power Module C1 BK Left Front Fender 26, 28
Integrated Power Module C2 WT Left Front Fender 26, 28
Integrated Power Module C3 GR Left Front Fender 26, 28
Integrated Power Module C4 WT Left Front Fender 26, 28
Integrated Power Module C5 BK Left Front Fender 26, 28
Integrated Power Module C6 BK Left Front Fender 25, 26, 28
Integrated Power Module C7 GY Left Front Fender 26, 28
Integrated Power Module FCM BK In IPM N/S
Knock Sensor BK Left Rear of Engine 5, 7, 9
License Lamp-Left BK At Rear Bumper 50, 51
License Lamp-Right BK At Rear Bumper 50, 51
Lift Pump Motor BK Near T/O for WIF Sensor N/S
Line Pressure Sensor BK Right Rear of Transmission 15, 18
Lumbar Motor-Driver DK GY At Driver Seat N/S
Lumbar Motor-Passenger BK At Passenger Seat N/S
Manifold Absolute Pressure Sensor GY Left Front of Intake Manifold 6
Mode Door Actuator 1 BK Right Side of HVAC N/S
DR8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 5
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

OPERATION
Fuel Pressure Regulator Operation:The pres-
sure regulator is a mechanical device that is not con-
trolled by engine vacuum or the Powertrain Control
Module (PCM).
The regulator is calibrated to maintain fuel system
operating pressure of approximately 58   2 psi at the
fuel injectors. It contains a diaphragm, calibrated
springs and a fuel return valve. The internal fuel fil-
ter (Fig. 2) is also part of the assembly.
Fuel is supplied to the filter/regulator by the elec-
tric fuel pump through an opening tube at the bot-
tom of filter/regulator (Fig. 2).
The regulator acts as a check valve to maintain
some fuel pressure when the engine is not operating.
This will help to start the engine. A second check
valve is located at the outlet end of the electric fuel
pump.Refer to Fuel Pump - Description and
Operation for more information.
If fuel pressure at the pressure regulator exceeds
approximately 60 psi, an internal diaphragm opens
and excess fuel pressure is routed back into the tank
through the bottom of pressure regulator.
Both fuel filters (at bottom of fuel pump module
and within fuel pressure regulator) are designed for
extended service. They do not require normal sched-
uled maintenance. Filters should only be replaced if
a diagnostic procedure indicates to do so.
FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel pump module has 4 different circuits
(wires). Two of these circuits are used for the fuel
gauge sending unit for fuel gauge operation, and for
certain OBD II emission requirements. The other 2
wires are used for electric fuel pump operation.
For Fuel Gauge Operation:A constant current
source is supplied to the resistor track on the fuel
gauge sending unit. This is fed directly from the
Powertrain Control Module (PCM).NOTE: For
diagnostic purposes, this 12V power source can
only be verified with the circuit opened (fuel
pump module electrical connector unplugged).
With the connectors plugged, output voltages
will vary from about 0.6 volts at FULL, to about
8.6 volts at EMPTY (about 8.6 volts at EMPTY
for Jeep models, and about 7.0 volts at EMPTY
for Dodge Truck models).The resistor track is
used to vary the voltage (resistance) depending on
fuel tank float level. As fuel level increases, the float
and arm move up, which decreases voltage. As fuel
level decreases, the float and arm move down, which
increases voltage. The varied voltage signal is
returned back to the PCM through the sensor return
circuit.
Both of the electrical circuits between the fuel
gauge sending unit and the PCM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the PCM, the PCM
will interpret the resistance (voltage) data and send
a message across the multi-plex bus circuits to the
instrument panel cluster. Here it is translated into
the appropriate fuel gauge level reading. Refer to
Instrument Panel for additional information.
For OBD II Emission Monitor Requirements:
The PCM will monitor the voltage output sent from
the resistor track on the sending unit to indicate fuel
level. The purpose of this feature is to prevent the
OBD II system from recording/setting false misfire
and fuel system monitor diagnostic trouble codes.
The feature is activated if the fuel level in the tank
is less than approximately 15 percent of its rated
capacity. If equipped with a Leak Detection Pump
(EVAP system monitor), this feature will also be acti-
vated if the fuel level in the tank is more than
approximately 85 percent of its rated capacity.
Fig. 2 SIDE VIEW - FILTER/REGULATOR
1 - INTERNAL FUEL FILTER
2 - FUEL FLOW TO FUEL INJECTORS
3 - FUEL FILTER/FUEL PRESSURE REGULATOR
4 - EXCESS FUEL BACK TO TANK
5 - FUEL INLET
6 - RUBBER GROMMET
7 - TOP OF PUMP MODULE
14 - 6 FUEL DELIVERY - GASDR
FUEL FILTER/PRESSURE REGULATOR (Continued)

FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel tank module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel tank module on diesel powered models
has 2 different circuits (wires). Two of these circuits
are used at the fuel gauge sending unit for fuel
gauge operation. The diesel engine does not have a
fuel tank module mounted electric fuel pump. The
electric fuel pump (fuel transfer pump) is mounted to
the engine.
For Fuel Gauge Operation:A constant input
voltage source of about 12 volts (battery voltage) is
supplied to the resistor track on the fuel gauge send-
ing unit. This is fed directly from the Engine Control
Module (ECM).NOTE: For diagnostic purposes,
this 12V power source can only be verified with
the circuit opened (fuel tank module electrical
connector unplugged). With the connectors
plugged, output voltages will vary from about .6
volts at FULL, to about 7.0 volts at EMPTY.The
resistor track is used to vary the voltage (resistance)
depending on fuel tank float level. As fuel level
increases, the float and arm move up, which
decreases voltage. As fuel level decreases, the float
and arm move down, which increases voltage. The
varied voltage signal is returned back to the ECM
through the sensor return circuit.
Both of the electrical circuits between the fuel
gauge sending unit and the ECM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the ECM, the ECM
will interpret the resistance (voltage) data and send
a message across the multi-plex bus circuits to the
instrument panel cluster. Here it is translated into
the appropriate fuel gauge level reading. Refer to
Instrument Panel for additional information.
REMOVAL
REMOVAL/INSTALLATION
For diesel removal and installation procedures,
refer to the gas section of Fuel System/Fuel Delivery.
See Fuel Level Sending Unit/Sensor Removal/Instal-
lation.
FUEL LINES
DESCRIPTION
Low-Pressure Lines Are:
²the fuel supply line from fuel tank to fuel trans-
fer (lift) pump.
²the fuel return line back to fuel tank.
²the fuel drain (manifold) line at rear of cylinder
head.
²the fuel supply line from fuel filter to fuel injec-
tion pump.
²the fuel injection pump return line.
High-Pressure Lines Are:
²the fuel line from fuel injection pump to fuel
rail.
²the 6 fuel lines from fuel rail up to injector con-
nector tubes
WARNING: HIGH-PRESSURE FUEL LINES DELIVER
DIESEL FUEL UNDER EXTREME PRESSURE FROM
THE INJECTION PUMP TO THE FUEL INJECTORS.
THIS MAY BE AS HIGH AS 160,000 KPA (23,206
PSI). USE EXTREME CAUTION WHEN INSPECTING
FOR HIGH-PRESSURE FUEL LEAKS. INSPECT FOR
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD. HIGH FUEL INJECTION PRESSURE
CAN CAUSE PERSONAL INJURY IF CONTACT IS
MADE WITH THE SKIN.
OPERATION
High-Pressure Lines
CAUTION: The high-pressure fuel lines must be
held securely in place in their holders. The lines
cannot contact each other or other components. Do
not attempt to weld high-pressure fuel lines or to
repair lines that are damaged. If lines are ever
kinked or bent, they must be replaced. Use only the
recommended lines when replacement of high-pres-
sure fuel line is necessary.
High-pressure fuel lines deliver fuel (under pres-
sure) of up to approximately 160,000 kPa (23,206
PSI) from the injection pump to the fuel injectors.
The lines expand and contract from the high-pres-
sure fuel pulses generated during the injection pro-
cess. All high-pressure fuel lines are of the same
length and inside diameter. Correct high-pressure
fuel line usage and installation is critical to smooth
engine operation.
DRFUEL DELIVERY - DIESEL 14 - 57

TRANSMISSION RANGE
SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) (Fig. 240)
has 3 primary functions:
²Provide a PARK/NEUTRAL start signal to the
engine controller and the starter relay.
²Turn the Back-up lamps on when the transmis-
sion is in REVERSE and the engine (ignition) is on.
²Provide a transmission range signal to the
instrument cluster.
The sensor is mounted in the transmission housing
near the valve body, just above the pan rail. It's in
the same position as the Park/Neutral switch on
other transmissions. The TRS contacts a cammed
surface on the manual valve lever. The cammed sur-
face translates the rotational motion of the manual
lever into the linear motion of the sensor. The
cammed surface on the manual lever is comprised of
two parts controlling the TRS signal: The insulator
portion contacts the switch poppet when the manual
lever is not in PARK or NEUTRAL. The manual
lever itself contacts the poppet when the lever is inPARK or NEUTRAL; providing a ground for the sig-
nal from the starter relay and the JTEC engine con-
troller.
OPERATION
As the switch moves through its linear motion (Fig.
241) contacts slide across a circuit board which
changes the resistance between the range sensing
pins of the switch. A power supply on the instrument
cluster provides a regulated voltage signal to the
switch. The return signal is decoded by the cluster,
which then controls the PRNDL display to corre-
spond with the correct transmission range. A bus
message of transmission range is also sent by the
cluster. In REVERSE range a second contact set
closes the circuit providing power to the reverse
lamps.
Fig. 240 Transmission Range Sensor
Fig. 241 Transmission Range Sensor Linear
Movement
DRAUTOMATIC TRANSMISSION - 48RE 21 - 263

INSTRUMENT PANEL
TABLE OF CONTENTS
page page
CLUSTER BEZEL
REMOVAL.............................49
INSTALLATION.........................49
ASH RECEIVER
REMOVAL.............................50
INSTALLATION.........................51
CUP HOLDER
REMOVAL.............................51
INSTALLATION.........................51
GLOVE BOX
REMOVAL.............................52
INSTALLATION.........................52
GLOVE BOX LATCH
REMOVAL.............................52
INSTALLATION.........................52
INSTRUMENT PANEL ASSEMBLY
REMOVAL.............................52
INSTALLATION.........................55
INSTRUMENT PANEL HEADLAMP SWITCH
BEZEL
REMOVAL.............................56
INSTALLATION.........................56INSTRUMENT PANEL CENTER BEZEL
REMOVAL.............................57
INSTALLATION.........................57
INSTRUMENT PANEL DRIVER SIDE BEZEL
REMOVAL.............................58
INSTALLATION.........................58
INSTRUMENT PANEL TOP COVER
REMOVAL.............................58
INSTALLATION.........................59
INSTRUMENT PANEL LOWER SURROUND
REMOVAL.............................59
INSTALLATION.........................59
STEERING COLUMN OPENING COVER
REMOVAL.............................60
INSTALLATION.........................60
STEERING COLUMN OPENING SUPPORT
BRACKET
REMOVAL.............................60
INSTALLATION.........................60
STORAGE BIN
REMOVAL.............................61
INSTALLATION.........................61
CLUSTER BEZEL
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, SEAT BELT TENSIONER, OR INSTRU-
MENT PANEL COMPONENT DIAGNOSIS OR SER-
VICE. DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE, THEN WAIT TWO
MINUTES FOR THE AIRBAG SYSTEM CAPACITOR
TO DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Remove the headlamp switch bezel. (Refer to
23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL SWITCH BEZEL - REMOVAL)
(2) Remove the center bezel. (Refer to 23 - BODY/
INSTRUMENT PANEL/INSTRUMENT PANEL
CENTER BEZEL - REMOVAL)(3) Remove the two top screws. (Fig. 1)
(4) Using a trim stick C-4755 or equivalent, sepa-
rate the two lower clips.
(5) Disengage the two top attachment bosses and
remove the bezel.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, SEAT BELT TENSIONER, OR INSTRU-
MENT PANEL COMPONENT DIAGNOSIS OR SER-
VICE. DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE, THEN WAIT TWO
MINUTES FOR THE AIRBAG SYSTEM CAPACITOR
TO DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Position the cluster bezel over the cluster and
seat the outer bosses over the posts on the left and
right sides.
DRINSTRUMENT PANEL 23 - 49

(2) Snap the top edge of the bezel into place fully.
(3) Seat the two bottom clips fully.
(4) Install the two top screws.
(5) Install the center bezel (Refer to 23 - BODY/
INSTRUMENT PANEL/INSTRUMENT PANEL
CENTER BEZEL - INSTALLATION)
(6) Install the headlamp switch bezel. (Refer to 23
- BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL SWITCH BEZEL - INSTALLATION)
ASH RECEIVER
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, SEAT BELT TENSIONER, OR INSTRU-
MENT PANEL COMPONENT DIAGNOSIS OR SER-
VICE. DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE, THEN WAIT TWO
MINUTES FOR THE AIRBAG SYSTEM CAPACITOR
TO DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.(1) Open ash receiver and place hand inside. (Fig.
2)
(2) Apply force with anabruptdownward motion
and roll rearward. (Fig. 3)
(3) Dislodge and roll ash receiver out of panel to
remove.
Fig. 1 CLUSTER BEZEL
1 - INSTRUMENT PANEL
2 - SCREWS (2)
3 - CLUSTER BEZEL
4 - CLIP FASTENERS (2)
Fig. 2 ASH RECEIVER
1 - ASH RECEIVER
2 - CUP HOLDER
Fig. 3 ASH RECEIVER REMOVAL
1 - LOCKING TABS
2 - CUP HOLDER
3 - ASH RECEIVER
23 - 50 INSTRUMENT PANELDR
CLUSTER BEZEL (Continued)