2003 DODGE RAM roof

INSTALLATION
(1) Press and hold the brake pedal down.
(2) Align the tab on thenewswitch with the notch
in the switch bracket. Insert the switch in the
bracket and turn it clockwise about 30É to lock it in
place.
(3) Connect the harness wires to the switch.
(4) Release the brake pedal.
(5) Move the release lever on the switch parallel
with the connector to engage the switch plunger. The
switch is now adjusted andcan notbe adjusted
again.
CENTER HIGH MOUNTED
STOP LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the CHMSL from the roof panel. Refer
to (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/CENTER HIGH MOUNTED STOP
LAMP UN - REMOVAL).
(3) Turn the bulb socket 1/4 turn counterclockwise.
(4) Separate the socket from the lamp.
(5) Remove the bulb.
INSTALLATION
(1) Position the bulb in the socket and press into
place.
(2) Position the socket in the lamp.
(3) Turn the bulb socket 1/4 turn clockwise.
(4) Install the CHMSL. Refer to (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
CENTER HIGH MOUNTED STOP LAMP UN -
INSTALLATION).
(5) Connect the battery negative cable.
CENTER HIGH MOUNTED
STOP LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove screws holding CHMSL to roof panel
(Fig. 4).
(3) Separate CHMSL from roof.
(4) Disengage wire connector from body wire har-
ness.
(5) Separate CHMSL from vehicle.
INSTALLATION
(1) Position lamp at cab roof and connect wire con-
nector.
(2) Install screws holding CHMSL to roof panel.
Tighten securely.
(3) Connect the battery negative cable.
CAB CLEARANCE LAMP
REMOVAL
(1) Remove both retaining screws and separate the
lamp from the roof.
(2) Quarter turn counter clockwise to separate
bulb socket from lamp.
INSTALLATION
(1) Quarter twist the bulb socket clockwise into
the lamp housing.
(2) Position the lamp assembly onto the roof and
install retaining screws. (Fig. 5)
Fig. 4 CENTER HIGH MOUNT STOP LAMP Ð
TYPICAL
1 - CHMSL CARGO LAMP HOUSING
2 - CHMSL
3 - CARGO LAMPS
4 - SCREW
5 - CLIP
6 - CAB
8L - 10 LAMPS/LIGHTING - EXTERIORDR
BRAKE LAMP SWITCH (Continued)

FOG LAMP
REMOVAL
NOTE: The fog lamps are serviced from the rear-
ward side of the front bumper.
(1) Disconnect and isolate the battery negative
cable.
(2) Disengage fog lamp harness connector.
(3) Remove the bolts attaching the fog lamp to the
bumper (Fig. 6).
(4) Separate fog lamp from bumper.
INSTALLATION
(1) Position fog lamp in bumper.
(2) Install the bolts attaching the fog lamp to the
bumper.
(3) Connect fog lamp harness connector.
(4) Connect the battery negative cable.
(5) Check for proper operation and beam align-
ment.
FOG LAMP RELAY
DESCRIPTION
The front fog lamp relay is located in the Power
Distribution Center (PDC) in the engine compart-
ment of the vehicle. The front fog lamp relay is a
conventional International Standards Organization
Fig. 5 CLEARANCE LAMP
1 - NUT
2 - CAB ROOF
3 - BULB SOCKET
4 - CLEARANCE LAMP
5 - SCREW
6 - BULB
Fig. 6 Fog Lamp
1 - SCREW
2 - FOG LAMP UNIT
3 - CONNECTOR
Fig. 7 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
DRLAMPS/LIGHTING - EXTERIOR 8L - 11
CAB CLEARANCE LAMP (Continued)

MESSAGE SYSTEMS
TABLE OF CONTENTS
page page
OVERHEAD CONSOLE
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING - OVERHEAD
CONSOLE............................2
STANDARD PROCEDURE
STANDARD PROCEDURE - READING/
COURTESY LAMP REPLACEMENT.........3
STANDARD PROCEDURE - MODULE LENS
REPLACEMENT.......................3
STANDARD PROCEDURE - MODULE LAMP
REPLACEMENT.......................3
STANDARD PROCEDURE - COMPASS
CALIBRATION.........................3
STANDARD PROCEDURE - COMPASS
DEMAGNETIZING......................4
STANDARD PROCEDURE - COMPASS
VARIATION ADJUSTMENT................4
REMOVAL
OVERHEAD CONSOLE REMOVAL.........5
INSTALLATION..........................5
SPECIAL TOOLS
OVERHEAD CONSOLE..................6
COMPASS/MINI-TRIP COMPUTER
DESCRIPTION..........................6
OPERATION............................7
DIAGNOSIS AND TESTING - COMPASS
MINI-TRIP COMPUTER..................7
REMOVAL.............................7
INSTALLATION..........................7
ELECTRONIC VEHICLE INFO CENTER
DESCRIPTION..........................7OPERATION............................8
DIAGNOSIS AND TESTING - ELECTRONIC
VEHICLE INFORMATION CENTER.........8
STANDARD PROCEDURE - ELECTRONIC
VEHICLE INFORMATION CENTER
PROGRAMMING.......................8
REMOVAL.............................10
INSTALLATION.........................10
AMBIENT TEMP SENSOR
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR...............11
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR CIRCUIT........11
REMOVAL.............................11
INSTALLATION.........................11
UNIVERSAL TRANSMITTER
DESCRIPTION.........................11
OPERATION...........................12
DIAGNOSIS AND TESTING - UNIVERSAL
TRANSMITTER.......................12
STANDARD PROCEDURE
STANDARD PROCEDURE - ERASING
TRANSMITTER CODES.................12
STANDARD PROCEDURE - SETTING
TRANSMITTER CODES.................12
REMOVAL.............................13
OVERHEAD CONSOLE
DESCRIPTION
Two different overhead consoles are available on
DR models. The Electronic Vehicle Information Cen-
ter (EVIC) (Fig. 1) or Compass Mini-Trip Computer
(CMTC). All consoles are equipped with two reading/
courtesy lamps. The overhead console is mounted
with screws and two snap clips to a molded plastic
retainer bracket located above the headliner.
COMPASS DISPLAY
All the available overhead consoles on this model
include Compass information. While in the compass/
temperature mode, the compass will display thedirection in which the vehicle is pointed using the
eight major compass headings (Examples: north is N,
northeast is NE). The self-calibrating compass unit
requires no adjusting in normal use. The only cali-
bration that may prove necessary is to drive the vehi-
cle at 5 to 8 kilometers-per-hour (3 to 5 miles-per-
hour), on level ground in a square shaped pattern.
This will reorient the compass unit to its vehicle.
The compass unit also will compensate for magne-
tism the body of the vehicle may acquire during nor-
mal use. However, avoid placing anything magnetic
directly on the roof of the vehicle. Magnetic mounts
for an antenna, a repair order hat, or a funeral pro-
cession flag can exceed the compensating ability of
the compass unit if placed on the roof panel. Mag-
netic bit drivers used on the fasteners that hold the
DRMESSAGE SYSTEMS 8M - 1

overhead console assembly to the roof header can
also affect compass operation. If the vehicle roof
should become magnetized, the demagnetizing and
calibration procedures found in this section may be
required to restore proper compass operation.
TEMPERATURE DISPLAY
All the available overhead consoles on this model
include Temperature information. The temperature
displays the outside ambient temperature in whole
degrees. The temperature display can be toggled
from Fahrenheit to Celsius by selecting the desired
U.S./Metric option from the customer programmable
features. The displayed temperature is not an instant
reading of conditions, but an average temperature. It
may take the temperature display several minutes to
respond to a major temperature change, such as driv-
ing out of a heated garage into winter temperatures.
When the ignition switch is turned to the Off posi-
tion, the last displayed temperature reading stays in
the electronic control modules, (CMTC, EVIC) mem-
ory. When the ignition switch is turned to the On
position again, the electronic module will display the
memory temperature for one minute; then update the
display to the current average temperature reading
within five minutes.
The temperature function is supported by an ambi-
ent temperature sensor. This sensor is mounted out-
side the passenger compartment near the front and
center of the vehicle, and is hard wired to the Front
Control Module (FCM). The FCM sends temperature
status messages to the module over the J1850 PCI
data bus circuit. For more information on the ambi-ent temperature sensor, refer to Ambient Tempera-
ture Sensor later in this section.
Following are general descriptions of the major
components used in the overhead console. Refer to
Wiring Diagrams for complete circuit schematics.
OPERATION
Refer to the vehicle Owner's Manual for specific
operation of each overhead console and its systems.
DIAGNOSIS AND TESTING - OVERHEAD
CONSOLE
If the problem with the overhead console is an
inaccurate or scrambled display, refer toSELF-DI-
AGNOSTIC TESTlater in this text. If the problem
with the overhead console is incorrect Vacuum Fluo-
rescent Display (VFD) dimming levels, use a DRB
IIItscan tool and the proper Diagnostic Procedures
manual to test for the correct dimming message
inputs being received from the Body Control Module
(BCM) or Front Control Module (FCM) over the
J1850 Programmable Communications Interface
(PCI) data bus circuit. If the problem is a no-display
condition, use the following procedure. For complete
circuit diagrams, refer toOverhead Consolein the
Wiring Diagrams section of the service manual.
(1) Remove the overhead console from the head-
liner (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE - REMOVAL).
(2) Check for battery voltage at the overhead con-
sole electrical connector. Refer to Wiring for connec-
tor information. If OK, go to Step 3. If not OK, Check
for battery voltage at the appropriate B(+) fuse in the
integrated power module, repair the open fused B(+)
circuit as required.
(3) Turn the ignition switch to the On position.
Check the fused ignition switch output circuit(s) at
the overhead console electrical connector. If OK, go to
Step 4. If not OK, repair the open or shorted circuit
as required.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Check for continuity between the ground circuit cav-
ity of the overhead console electrical connector and a
good ground. There should be continuity. If OK, refer
toSELF-DIAGNOSTIC TESTbelow for further
diagnosis of the electronics module and the J1850
PCI data bus circuit. If not OK, repair the open
ground circuit as required.
SELF-DIAGNOSTIC TEST
A self-diagnostic test is built-in to the module to
determine that the electronics module is operating
properly, and that all the J1850 PCI data bus mes-
sages are being received for proper operation. To per-
form the self-diagnostic test proceed as follows:
Fig. 1 DR OVERHEAD CONSOLE ± EVIC
8M - 2 MESSAGE SYSTEMSDR
OVERHEAD CONSOLE (Continued)

(1) With the ignition switch in the Off position,
simultaneously depress and hold theSTEP and
RESET buttons.
(2) Turn the ignition switch to the On position.
(3) Following completion of the test, the electronics
module will display one of the following messages:
a.Pass Self Test (EVIC only), PASS (CMTC)-
The electronics module is working properly.
b.Failed Self Test (EVIC only), FAIL (CMTC)-
The electronics module has an internal failure. The
electronics module is faulty and must be replaced.
c.Failed J1850 Communication (EVIC only),
BUS (CMTC)- The electronics module is not receiv-
ing proper message input through the J1850 PCI
data bus circuit. This can result from one or more
faulty electronic modules in the vehicle, or from a
faulty PCI data bus. The use of a DRB IIItscan tool
and the proper Diagnostic Procedures manual are
required for further diagnosis.
NOTE: If the compass functions, but accuracy is
suspect, it may be necessary to perform a variation
adjustment. This procedure allows the compass
unit to accommodate variations in the earth's mag-
netic field strength, based on geographic location.
Refer to Compass Variation Adjustment in the Stan-
dard Procedures section of this group.
NOTE: If the compass reading displays dashes, and
only ªCALº appears in the display, demagnetizing
may be necessary to remove excessive residual
magnetic fields from the vehicle. Refer to Compass
Demagnetizing in the Standard Procedures section
of this group.
STANDARD PROCEDURE
STANDARD PROCEDURE - READING/
COURTESY LAMP REPLACEMENT
(1) Open hood, disconnect and isolate the negative
battery cable.
(2) Remove the reading/courtesy lamp lens. Using
a trim stick, gently pry the forward edge of the read-
ing/courtesy lamp lens outward.
(3) Remove the reading/courtesy lamp socket from
the overhead console. Rotate the reading/courtesy
lamp socket one quarter turn counter clockwise.
(4) Remove the lamp and socket assembly.
(5) Reverse the above procedure to install.
STANDARD PROCEDURE - MODULE LENS
REPLACEMENT
(1) Remove the overhead console (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOV-
AL).
(2) Remove the electronics module from the over-
head console. Refer to the procedure later in this sec-
tion.
(3) Unsnap the lens from the module and replace
lens as necessary.
STANDARD PROCEDURE - MODULE LAMP
REPLACEMENT
(1) Remove the overhead console (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOV-
AL).
(2) Using a flat blade screwdriver twist out socket/
lamp (Fig. 2).
(3) Replace lamp(s) as necessary.
STANDARD PROCEDURE - COMPASS
CALIBRATION
CAUTION: Do not place any external magnets, such
as magnetic roof mount antennas, in the vicinity of
the compass. Do not use magnetic tools when ser-
vicing the overhead console.
Fig. 2 Top of Overhead Console
1 - OVERHEAD CONSOLE HOUSING
2 - EVIC/CMTC MODULE
3 - ILLUMINATION LAMPS
4 - MODULE RETAINING SCREWS
DRMESSAGE SYSTEMS 8M - 3
OVERHEAD CONSOLE (Continued)

The electronic compass unit features a self-cali-
brating design, which simplifies the calibration pro-
cedure. This feature automatically updates the
compass calibration while the vehicle is being driven.
This allows the compass unit to compensate for small
changes in the residual magnetism that the vehicle
may acquire during normal use. If the compass read-
ings appear to be erratic or out of calibration, per-
form the following calibration procedure. Also, new
service replacement Electronic Modules (EVIC,
CMTC) must have their compass calibrated using
this procedure. Do not attempt to calibrate the com-
pass near large metal objects such as other vehicles,
large buildings, or bridges; or, near overhead or
underground power lines.
NOTE: Whenever the compass is calibrated manu-
ally, the variance number must also be reset. Refer
to Compass Variation Adjustment in this group.
To calibrate the compass manually proceed as fol-
lows:
(1) Turn the ignition switch to the On position. If
the compass/temperature data is not currently being
displayed, momentarily depress and release the C/T
push button to reach the compass/temperature dis-
play.
(2) Depress the RESET push button and hold the
button down until ªCALº appears in the display. This
takes about ten seconds, and appears about five sec-
onds after ªVAR = XXº is displayed.
(3) Release the RESET push button.
(4) Drive the vehicle on a level surface, away from
large metal objects and power lines, through three or
more complete turns at between five and eight kilo-
meters-per-hour (three and five miles-per-hour) in
not less than 48 seconds. The ªCALº message will
disappear from the display to indicate that the com-
pass is now calibrated.
NOTE: If the ªCALº message remains in the display,
either there is excessive magnetism near the com-
pass, or the unit is faulty. Repeat the calibration
procedure one more time.
NOTE: If the wrong direction is still indicated in the
compass display, the area selected for calibration
may be too close to a strong magnetic field. Repeat
the calibration procedure in another location.
STANDARD PROCEDURE - COMPASS
DEMAGNETIZING
A degaussing tool (Special Tool 6029) is used to
demagnetize, or degauss, the overhead console for-
ward mounting screw and the roof panel above theoverhead console. Equivalent units must be rated as
continuous duty for 110/115 volts and 60 Hz. They
must also have a field strength of over 350 gauss at 7
millimeters (0.25 inch) beyond the tip of the probe.
To demagnetize the roof panel and the overhead
console forward mounting screw, proceed as follows:
(1) Be certain that the ignition switch is in the Off
position, before you begin the demagnetizing proce-
dure.
(2) Connect the degaussing tool to an electrical
outlet, while keeping the tool at least 61 centimeters
(2 feet) away from the compass unit.
(3) Slowly approach the head of the overhead con-
sole mounting screw with the degaussing tool con-
nected.
(4) Contact the head of the screw with the plastic
coated tip of the degaussing tool for about two sec-
onds.
(5) With the degaussing tool still energized, slowly
back it away from the screw. When the tip of the tool
is at least 61 centimeters (2 feet) from the screw
head, disconnect the tool.
(6) Place a piece of paper approximately 22 by 28
centimeters (8.5 by 11 inches), oriented on the vehicle
lengthwise from front to rear, on the center line of
the roof at the windshield header (Fig. 3). The pur-
pose of the paper is to protect the roof panel from
scratches, and to define the area to be demagnetized.
(7) Connect the degaussing tool to an electrical
outlet, while keeping the tool at least 61 centimeters
(2 feet) away from the compass unit.
(8) Slowly approach the center line of the roof
panel at the windshield header, with the degaussing
tool connected.
(9) Contact the roof panel with the plastic coated
tip of the degaussing tool. Be sure that the template
is in place to avoid scratching the roof panel. Using a
slow, back-and-forth sweeping motion, and allowing
13 millimeters (0.50 inch) between passes, move the
tool at least 11 centimeters (4 inches) to each side of
the roof center line, and 28 centimeters (11 inches)
back from the windshield header.
(10) With the degaussing tool still energized,
slowly back it away from the roof panel. When the
tip of the tool is at least 61 centimeters (2 feet) from
the roof panel, disconnect the tool.
(11) Calibrate the compass and adjust the compass
variance (Refer to 8 - ELECTRICAL/OVERHEAD
CONSOLE - STANDARD PROCEDURE).
STANDARD PROCEDURE - COMPASS
VARIATION ADJUSTMENT
Compass variance, also known as magnetic decli-
nation, is the difference in angle between magnetic
north and true geographic north. In some geographic
locations, the difference between magnetic and geo-
8M - 4 MESSAGE SYSTEMSDR
OVERHEAD CONSOLE (Continued)

graphic north is great enough to cause the compass
to give false readings. If this problem occurs, the
compass variance setting may need to be changed.
To set the compass variance:
(1) Using the Variance Settings map, find your
geographic location and note the zone number (Fig.
4).
(2) Turn the ignition switch to the On position. If
the compass/temperature data is not currently being
displayed, momentarily depress and release the C/T
push button to reach the compass/temperature dis-
play.
(3) Depress theRESETpush button and hold the
button down until ªVAR = XXº appears in the display.
This takes about five seconds.(4) Release theRESETpush button. ªVAR =XX º
will remain in the display. ªXXº equals the current
variance zone setting.
(5) Depress and release theSTEPpush button to
step through the zone numbers, until the zone num-
ber for your geographic location appears in the dis-
play.
(6) Depress and release theRESETpush button
to enter the displayed zone number into the EVIC/
CMTC module memory.
(7) Confirm that the correct directions are now
indicated by the compass.
REMOVAL
OVERHEAD CONSOLE REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the overhead console retaining screws,
located in the sunglass storage bin.
(3) Using your fingertips, grasp the sides of the
overhead console and pull straight down evenly to
disengage the two snap clips at the front of the unit.
(4) Lower the overhead console far enough to
access the wire harness connectors.
(5) Disconnect the EVIC, CMTC electronic module
and the reading/courtesy lamps electrical connectors.
(6) Remove the overhead console from the vehicle.
INSTALLATION
(1) Position the overhead console in the vehicle.
(2) Connect the EVIC, CMTC electronic module
and the reading/courtesy lamps electrical connectors.
(3) Grasp the sides of the overhead console and
push straight up evenly to engage the two snap clips
at the rear of the unit.
(4) Install the overhead console retaining screw,
located in the front of console. Torque the screw to
1.2 N´m (10 in. lbs.).
(5) Connect the negative battery cable.
Fig. 3 Roof Demagnetizing Pattern
DRMESSAGE SYSTEMS 8M - 5
OVERHEAD CONSOLE (Continued)

²Clockspring- The clockspring is located near
the top of the steering column, directly beneath the
steering wheel.
²Driver Airbag- The driver airbag is located in
the center of the steering wheel, beneath the driver
airbag trim cover.
²Driver Knee Blocker- The driver knee blocker
is a structural unit secured to the back side of and
integral to the instrument panel steering column
opening cover.
²Passenger Airbag- The passenger airbag is
located on the instrument panel, beneath the passen-
ger airbag door on the instrument panel above the
glove box on the passenger side of the vehicle.
²Passenger Airbag On/Off Switch- Standard
cab models without a rear seat are equipped with a
passenger airbag on/off switch, which is located on
the right side of the instrument panel center bezel.
²Passenger Knee Blocker- The passenger knee
blocker is a structural reinforcement that is integral
to and concealed within the glove box door.
²Seat Belt Tensioner- The seat belt tensioner
is integral to the front outboard seat belt retractor
units on vehicles equipped with dual front airbags.
²Side Impact Airbag Control Module-Two
Side Impact Airbag Control Modules (SIACM) are
used on vehicles with the optional side curtain air-
bags, one left side and one right side. One SIACM is
located behind the B-pillar trim above the outboard
front seat belt retractor within each B-pillar.
²Side Curtain Airbag- In vehicles equipped
with this option, a side curtain airbag is located on
each inside roof side rail above the headliner, and
extends from the A-pillar to the B-pillar on standard
cab models, and from the A-pillar to the C-pillar on
quad cab models.
The ACM, both SIACMs, and the EMIC each con-
tain a central processing unit and programming that
allow them to communicate with each other usingthe Programmable Communications Interface (PCI)
data bus network. This method of communication is
used by the ACM for control of the airbag indicator
on all models equipped with dual front airbags.
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/COMMUNICATION - DESCRIP-
TION).
Hard wired circuitry connects the supplemental
restraint system components to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system,
and to the supplemental restraint system compo-
nents through the use of a combination of soldered
splices, splice block connectors, and many different
types of wire harness terminal connectors and insu-
lators. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.
OPERATION
ACTIVE RESTRAINTS
The primary passenger restraints in this or any
other vehicle are the standard equipment factory-in-
stalled seat belts and child restraint anchors. Seat
belts and child restraint anchors are referred to as
an active restraint because the vehicle occupants are
required to physically fasten and properly adjust
these restraints in order to benefit from them. See
the owner's manual in the vehicle glove box for more
information on the features, use and operation of all
of the factory-installed active restraints.
PASSIVE RESTRAINTS
The passive restraints are referred to as a supple-
mental restraint system because they were designed
and are intended to enhance the protection for the
occupants of the vehicleonlywhen used in conjunc-
tion with the seat belts. They are referred to as pas-
sive restraints because the vehicle occupants are not
required to do anything to make them operate; how-
ever, the vehicle occupants must be wearing their
seat belts in order to obtain the maximum safety
benefit from the factory-installed supplemental
restraint system.
The supplemental restraint system electrical cir-
cuits are continuously monitored and controlled by a
microprocessor and software contained within the
Airbag Control Module (ACM) and, on vehicles
equipped with the side curtain airbags, both Side
Fig. 2 SRS Logo
8O - 4 RESTRAINTSDR
RESTRAINTS (Continued)