ad blue DODGE RAM 2003 Service User Guide

sages to the Front Control Module (FCM) over the
Programmable Communications Interface (PCI) data
bus and flashes the turn signal indicators on and off
accordingly. For further diagnosis of the turn signal
indicators or the instrument cluster circuitry that
controls the indicators, (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the turn signal
and hazard warning system, the multi-function
switch, the FCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the turn signal indicators, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
UPSHIFT INDICATOR
DESCRIPTION
An upshift indicator is standard equipment on all
instrument clusters. However, on vehicles not
equipped with a manual transmission, this indicator
is electronically disabled. The upshift indicator con-
sists of an upward pointed arrow icon, which appears
on the right side of the electronic gear selector indi-
cator 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 speedom-
eter 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 light-
ing level as the odometer/trip odometer information
when it is illuminated by the instrument cluster elec-
tronic 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 inany 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 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.
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
8J - 40 INSTRUMENT CLUSTERDR
TURN SIGNAL INDICATOR (Continued)

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. 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 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 voltage gauge is serviced as
a unit with the instrument cluster.
OPERATION
The voltage gauge gives an indication to the vehi-
cle operator of the electrical system voltage. 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 voltage gauge is
an air core magnetic unit that receives battery cur-
rent 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 left 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:
²System Voltage Message- Each time the clus-
ter receives a system voltage message from the PCM
or ECM indicating the system voltage is between
about 9.5 volts and about 15 volts, the gauge needle
is moved to the relative voltage position on the gauge
scale.
²System Voltage Low (Charge Fail) Message
- Each time the cluster receives three consecutive
messages from the PCM or ECM indicating the elec-
trical system voltage is less than about 9 volts
(charge fail condition), the gauge needle is moved to
the graduation on the far left end of the gauge scale
and the check gauges indicator is illuminated. The
gauge needle remains at the far left end of the gauge
scale and the check gauges indicator remains illumi-
nated until the cluster receives a single message
from the PCM or ECM indicating the electrical sys-tem voltage is greater than about 9.5 volts (but less
than about 15.5 volts), or until the ignition switch is
turned to the Off position, whichever occurs first. On
vehicles equipped with the optional diesel engine, the
ECM is programmed to restrict the voltage gauge
needle to a position above the graduation on the far
left end of the gauge scale and suppress the check
engine indicator operation until after the engine
intake manifold air heater has completed a pre-heat
or post-heat cycle.
²System Voltage High Message- Each time
the cluster receives three consecutive messages from
the PCM or ECM indicating the electrical system
voltage is greater than about 15.5 volts, the gauge
needle is moved to the graduation on the far right
end of the gauge scale and the check gauges indica-
tor is illuminated. The gauge needle remains at the
right end of the gauge scale and the check gauges
indicator remains illuminated until the cluster
receives a message from the PCM or ECM indicating
the electrical system voltage is less than about 15.0
volts (but greater than about 9.5 volts), or until the
ignition switch is turned to the Off position, which-
ever occurs first.
²Communication Error- If the cluster fails to
receive a system voltage message, it will hold the
gauge needle at the last indication for about five sec-
onds or until the ignition switch is turned to the Off
position, whichever occurs first. After five seconds,
the cluster will move the gauge needle to the far left
end of the gauge scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the voltage gauge 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.
On vehicles with a gasoline engine, the PCM con-
tinually monitors the system voltage to control the
generator output. On vehicles with a diesel engine,
the ECM continually monitors the system voltage to
control the generator output. The PCM or ECM then
sends the proper system voltage messages to the
instrument cluster. For further diagnosis of the volt-
age gauge or the instrument cluster circuitry that
controls the gauge, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND TEST-
ING). If the instrument cluster turns on the check
gauges indicator due to a charge fail or voltage high
condition, it may indicate that the charging system
requires service. For proper diagnosis of the charging
system, the PCM, the ECM, the PCI data bus, or the
electronic message inputs to the instrument cluster
that control the voltage gauge, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
DRINSTRUMENT CLUSTER 8J - 41
VOLTAGE GAUGE (Continued)

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
Built-Up-Export....... Vehicles Built For Sale In
Markets Other Than North America
Except Built-Up-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 MOTOR - WHITE 2 WAY
CAV CIRCUIT FUNCTION
1 Y151 18LG/BR ADJUSTABLE PEDAL MOTOR (DOWN)
2 Y152 18LG/OR ADJUSTABLE PEDAL MOTOR (UP)
ADJUSTABLE PEDAL SWITCH - BLUE 6 WAY
CAV CIRCUIT FUNCTION
1 Y151 18LG/BR ADJUSTABLE PEDAL MOTOR (DOWN)
2 Y153 18DB/RD ADJUSTABLE PEDAL RELAY OUTPUT
3- -
4 Z154 18BK/BR GROUND
5 F15 20DB FUSED IGNITION SWITCH OUTPUT (RUN)
6 Y152 18LG/OR ADJUSTABLE PEDAL MOTOR (UP)
AIRBAG CONTROL MODULE - YELLOW 23 WAY
CAV CIRCUIT FUNCTION
1- -
2- -
3- -
4 Z6 18BK/PK GROUND
5 R45 18DG/LB DRIVER SQUIB 1 LINE 2
6 R43 18BK/LB DRIVER SQUIB 1 LINE 1
7 R42 18BK/YL PASSENGER SQUIB 1 LINE 1
8 R44 18DG/YL PASSENGER SQUIB 1 LINE 2
9 R53 18LG/YL RIGHT SEAT BELT TENSIONER LINE 2
10 R55 18LG/DG RIGHT SEAT BELT TENSIONER LINE 1
11 R56 18LB/DG LEFT SEAT BELT TENSIONER LINE 1
12 R54 18LB/YL LEFT SEAT BELT TENSIONER LINE 2
13 - -
14 F14 18LG/YL FUSED IGNITION SWITCH OUTPUT (RUN-START)
15 F23 18DB/YL FUSED IGNITION SWITCH OUTPUT (RUN)
16 - -
17 - -
18 - -
19 R4 18BR/YL PASSENGER AIRBAG MUX SWITCH RETURN
20 R5 18VT/YL PASSENGER AIRBAG MUX SWITCH SENSE
21 D25 20VT/DG PCI BUS
22 R166 18LG/TN PASSENGER AIRBAG INDICATOR DRIVER
23 - -
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 7

DOOR LOCK MOTOR/AJAR SWITCH-RIGHT REAR (EXCEPT BASE) - BLACK 4 WAY
CAV CIRCUIT FUNCTION
1 G76 20VT/OR RIGHT REAR DOOR AJAR SWITCH SENSE
2 Z74 20BK GROUND
3 Y156 18TN/OR DOOR UNLOCK DRIVER RIGHT DOORS
4 Y200 18TN/PK DOOR LOCK DRIVER RIGHT DOORS
DOOR LOCK SWITCH-PASSENGER - WHITE 6 WAY
CAV CIRCUIT FUNCTION
1 P96 20WT/LG PASSENGER DOOR LOCK SWITCH MUX
2 Y107 20VT/RD FUSED IGNITION SWITCH OUTPUT (RUN-START)
3- -
4- -
5 Z74 20BK/LG GROUND
6- -
DOOR WINDOW/LOCK SWITCH - PASSENGER - BLUE 6 WAY
CAV CIRCUIT FUNCTION
1 Q12 14BR RIGHT FRONT WINDOW DRIVER (UP)
2 Q26 14VT/WT MASTER WINDOW SWITCH RIGHT FRONT (DOWN)
3- -
4 Q16 14BR/WT MASTER WINDOW SWITCH RIGHT FRONT (UP)
5 Q22 14VT RIGHT FRONT WINDOW DRIVER (DOWN)
6 Q1 14YL POWER WINDOW SWITCH FEED
DRIVER BLEND DOOR ACTUATOR (DUAL-ZONE)-2WAY
CAV CIRCUIT FUNCTION
1 C34 20DB/WT COMMON DOOR DRIVER
2 C62 20DB/PK BLEND DOOR DRIVER
8W - 80 - 52 8W-80 CONNECTOR PIN-OUTSDR

DRIVER DOOR MODULE C1 - BLUE 12 WAY
CAV CIRCUIT FUNCTION
1 Q28 14DG/WT RIGHT REAR WINDOW DRIVER (DOWN)
2 Q18 14GY/BK RIGHT REAR WINDOW DRIVER (UP)
3 Q16 14BR/WT MASTER WINDOW SWITCH RIGHT FRONT (UP)
4 Q17 14DB/WT LEFT REAR WINDOW DRIVER (UP)
5 Q11 14LB LEFT FRONT WINDOW DRIVER (UP)
6 Q26 14VT/WT MASTER WINDOW SWITCH RIGHT FRONT (DOWN)
7 P97 20WT/DG DRIVER DOOR LOCK SWITCH MUX
8 Z67 14BK GROUND
9 F21 14TN FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
10 Q27 14RD/BK LEFT REAR WINDOW DRIVER (DOWN)
11 Z75 20BK GROUND
12 Q21 14WT LEFT FRONT WINDOW DRIVER (DOWN)
DRIVER DOOR MODULE C2 - BLUE 8 WAY
CAV CIRCUIT FUNCTION
1 P71 20YL LEFT MIRROR UP DRIVER
2 P76 20OR/YL LEFT MIRROR COMMON DRIVER (RIGHT/DOWN)
3 F32 18RD/YL FUSED B(+)
4 P74 20DB RIGHT MIRROR LEFT DRIVER
5 Z239 20BK GROUND
6 P75 20DB/WT LEFT MIRROR LEFT DRIVER
7 P72 20YL/BK RIGHT MIRROR UP DRIVER
8 Q1 14YL POWER WINDOW SWITCH FEED
DRIVER HEATED SEAT CUSHION - DK GRAY 4 WAY
CAV CIRCUIT FUNCTION
1 P141 18TN/LB DRIVER SEAT TEMPERATURE SENSOR INPUT
2 Z121 20BK/LG GROUND
3 P143 20BK/DG DRIVER SEAT TEMPERATURE 5 VOLT SUPPLY
4 P86 20PK/BK SEAT HEATER DRIVER
ELECTRIC BRAKE PROVISION - BLUE 4 WAY
CAV CIRCUIT FUNCTION
1 Y133 14RD/OR FUSED B(+)
2 B40 14LB TRAILER TOW BRAKE B(+)
3 L50 18WT/TN BRAKE LAMP SWITCH OUTPUT
4 Z255 18DG/BK GROUND
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 53

HEADLAMP-LEFT - BLUE 3 WAY
CAV CIRCUIT FUNCTION
1 Y171 18WT/DG LEFT LOW BEAM OUTPUT
2 Z141 18BK/LB GROUND
3 Y170 18WT/LG LEFT HIGH BEAM OUTPUT
HEADLAMP-RIGHT - BLUE 3 WAY
CAV CIRCUIT FUNCTION
1 Y169 18WT/TN RIGHT LOW BEAM OUTPUT
2 Z142 18BK/LG GROUND
3 Y168 18WT/LB RIGHT HIGH BEAM OUTPUT
HEATED SEAT CUSHION-PASSENGER - BLUE 4 WAY
CAV CIRCUIT FUNCTION
1 P142 20TN/DB PASSENGER SEAT TEMPERATURE SENSOR INPUT
2 Z121 20BK/WT GROUND
3 P144 20BK/LG PASSENGER SEAT TEMPERATURE 5 VOLT SUPPLY
4 P86 20PK/BK SEAT HEATER DRIVER
HEATED SEAT SWITCH-DRIVER - RED 6 WAY
CAV CIRCUIT FUNCTION
1 P137 20VT/DG DRIVER SEAT LOW HEAT LED DRIVER
2 Y161 20OR/RD PANEL LAMPS FEED
3 Z259 20BK/LG GROUND
4 P131 20RD/DG HEATED SEAT SWITCH SUPPLY
5 P139 20VT/WT DRIVER SEAT HIGH HEAT LED DRIVER
6 P133 20TN/DG DRIVER SEAT HEATER MUX SWITCH
8W - 80 - 64 8W-80 CONNECTOR PIN-OUTSDR

HEATED SEAT SWITCH-PASSENGER - BLUE 6 WAY
CAV CIRCUIT FUNCTION
1 P138 20VT/LG PASSENGER SEAT LOW HEAT LED DRIVER
2 Y161 20OR/RD PANEL LAMPS FEED
3 Z260 20DG/BK GROUND
4 P131 20RD/DG HEATED SEAT SWITCH SUPPLY
5 P140 20VT/BK PASSENGER SEAT HIGH HEAT LED DRIVER
6 P134 20TN/LG PASSENGER SEAT HEATER MUX SWITCH
HORN SWITCH - WHITE 2 WAY
CAV CIRCUIT FUNCTION
1 X3 20BK/RD HORN SWITCH SENSE
2- -
HORN-HIGH NOTE - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 X2 18DG/RD HORN RELAY OUTPUT
2 Z307 18BK/WT GROUND
HORN-LOW NOTE - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 X2 18DG/RD HORN RELAY OUTPUT
2 Z308 18BK/BR GROUND
IDLE AIR CONTROL MOTOR (3.7L/5.9L/8.0L) - BLACK 4 WAY
CAV CIRCUIT FUNCTION
C K39 18GY/RD IDLE AIR CONTROL MOTOR NO. 3 DRIVER
B K60 18YL/BK IDLE AIR CONTROL MOTOR NO. 2 DRIVER
A K40 18BR/WT IDLE AIR CONTROL MOTOR NO. 1 DRIVER
D K59 18VT/BK IDLE AIR CONTROL MOTOR NO. 4 DRIVER
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 65

MODE DOOR ACTUATOR 1 (PANEL TO FLOOR)-2WAY
CAV CIRCUIT FUNCTION
1 C34 20DB/WT COMMON DOOR DRIVER
2 C35 20DG/YL MODE DOOR 1 DRIVER
MODE DOOR ACTUATOR 2 (DEFROST TO FLOOR)-2WAY
CAV CIRCUIT FUNCTION
1 C34 20DB/WT COMMON DOOR DRIVER
2 C33 20DB/RD MODE DOOR 2 DRIVER
MULTI-FUNCTION SWITCH - BLACK 4 WAY
CAV CIRCUIT FUNCTION
1 Y109 20VT/OR WASH/BEAM SELECT SWITCH SIGNAL
2 Y108 20VT/BR WIPER/TURN/BEAM SELECT SWITCH RETURN
3 Y110 20WT/VT TURN LAMPS SWITCH SIGNAL
4 V8 20VT INTERMITTENT WIPER SWITCH SIGNAL
OUTPUT SPEED SENSOR (3.7L/4.7L/5.7L) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 T14 18LG/WT OUTPUT SPEED SENSOR SIGNAL
2 T13 18DB/BK SPEED SENSOR GROUND
OUTPUT SPEED SENSOR (5.9L) - DK BLUE 2 WAY
CAV CIRCUIT FUNCTION
1 T14 18LG/WT OUTPUT SPEED SENSOR SIGNAL
2 T13 18DB/BK SPEED SENSOR GROUND
DR8W-80 CONNECTOR PIN-OUTS 8W - 80 - 77

POWER WINDOW SWITCH-LEFT REAR - BLUE 6 WAY
CAV CIRCUIT FUNCTION
1 Q13 14DB DRIVER REAR WINDOW DRIVER (UP)
2 Q27 14RD/BK LEFT REAR WINDOW DRIVER (DOWN)
3- -
4 Q17 14DB/WT LEFT REAR WINDOW DRIVER (UP)
5 Q23 14RD/WT DRIVER REAR WINDOW DRIVER (DOWN)
6 Q1 14YL POWER WINDOW SWITCH FEED
POWER WINDOW SWITCH-RIGHT REAR - BLUE 6 WAY
CAV CIRCUIT FUNCTION
1 Q12 14DB PASSENGER REAR WINDOW DRIVER (UP)
2 Q28 14RD/BK RIGHT REAR WINDOW DRIVER (DOWN)
3- -
4 Q18 14DB/WT RIGHT REAR WINDOW DRIVER (UP)
5 Q24 14RD/WT PASSENGER REAR WINDOW DRIVER (DOWN)
6 Q1 14YL POWER WINDOW SWITCH FEED
POWER WINDOW-CIRCUIT BREAKER - GRAY 2 WAY
CAV CIRCUIT FUNCTION
1 F1 10DB IGNITION SWITCH OUTPUT (RUN-ACC)
2 F21 12TN FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
POWERTRAIN CONTROL MODULE - C1 (DIESEL) - 32 WAY
CAV CIRCUIT FUNCTION
1- -
2 Y135 18LG/BK FUSED IGNITION SWITCH OUTPUT (RUN-START)
3- -
4 K914 18VT/RD SENSOR GROUND
5- -
6 T24 18GY/BK PARK/NEUTRAL POSITION SWITCH SENSE (T41)
7- -
8 K24 18GY/BK CRANKSHAFT POSITION SENSOR SIGNAL
9- -
10 - -
11 - -
12 - -
13 - -
14 - -
15 - -
16 - -
17 - -
18 - -
19 - -
20 - -
21 - -
22 A14 18RD/WT FUSED B(+)
23 K22 18OR/DB ACCELERATOR PEDAL POSITION SENSOR SIGNAL
8W - 80 - 84 8W-80 CONNECTOR PIN-OUTSDR