2002 DODGE RAM ECU

(2) Engage license plate lamp wire connector to
body wire harness.
(3) Install screws attaching license plate panel to
cargo box.
(4) Connect the battery negative cable.
MARKER LAMP
REMOVAL
Individual lamps may be replaced by removing the
lamp from the light bar. Using a flat blade screw-
driver, carefully pry lamp to disengage clips attach-
ing ID lamp to retainer.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove four screws attaching rear ID lamps to
tailgate (Fig. 23).
(3) Separate ID lamps from tailgate.
(4) Disengage ID lamp wire connector from body
wire harness.
(5) Separate ID lamp from vehicle.
INSTALLATION
(1) Position ID lamp on vehicle.
(2) Engage ID lamp wire connector to body wire
harness.
(3) Install screws attaching rear ID lamps to tail-
gate.
(4) Connect the battery negative cable.
MULTI-FUNCTION SWITCH
DESCRIPTION
The multi-function switch is secured with two
screws to the left side of the upper steering column
housing at the top of the steering column, just below
the steering wheel (Fig. 24). The only visible parts of
the multi-function switch are the control stalk that
extends through a dedicated opening in the left side
of the upper steering column shrouds, and the haz-
ard warning switch push button that protrudes
through an opening in the upper steering column
shroud on the top of the steering column. The
remainder of the switch, its mounting provisions, and
its electrical connections are all concealed beneath
the steering column shrouds. The multi-function
switch control stalk has both nomenclature and
International Control and Display Symbol graphics
applied to it, which identify its many functions. An
International Control and Display Symbol icon for
ªHazard Warningº is applied to the top of the hazard
warning switch push button.
The switch housing and its controls are constructed
of molded black plastic. A single connector receptacle
with up to twenty-four terminals is located on the
back of the switch housing and connects the switch
to the vehicle electrical system through a take out
and connector of the instrument panel wire harness.
The connector receptacle also has a threaded recep-
tacle for a screw, which secures the wire harness con-
nector to the switch connector receptacle.
The multi-function switch supports the following
functions and features:
Fig. 23 Rear Identification Lamps
1 - BUMPER
2 - SCREW
3 - TAILGATE MARKER LAMPS
4 - TAILGATE
Fig. 24 Multi-Function Switch
1 - WINDSHIELD WASHER BUTTON
2 - CONTROL STALK
3 - HAZARD WARNING BUTTON
4 - WINDSHIELD WIPER CONTROL
5 - MULTI-FUNCTION SWITCH
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 23
LICENSE PLATE LAMP UNIT (Continued)

²Continuous Wipe Modes- The control knob of
the multi-function switch provides two continuous
wipe switch positions, low speed or high speed.
²Hazard Warning Control- The internal cir-
cuitry and hardware of the multi-function switch pro-
vide detent switching for activation and deactivation
of the hazard warning system.
²Headlamp Beam Selection- The internal cir-
cuitry and hardware of the multi-function switch pro-
vide detent switching for selection of the headlamp
high or low beams.
²Headlamp Optical Horn- The internal cir-
cuitry and hardware of the multi-function switch
includes momentary switching of the headlamp high
beam circuits to provide an optical horn feature
(sometimes referred to as flash-to-pass), which allows
the vehicle operator to momentarily flash the head-
lamp high beams as an optical signalling device.
²Intermittent Wipe Mode- The control knob of
the multi-function switch provides an intermittent
wipe mode with multiple delay interval positions.
²Turn Signal Control- The internal circuitry
and hardware of the multi-function switch provide
both momentary non-detent switching and detent
switching with automatic cancellation for both the
left and right turn signals.
²Washer Mode- A button on the end of the con-
trol stalk of the multi-function switch provides
washer system operation when the button is
depressed towards the steering column.
The multi-function switch cannot be adjusted or
repaired. If any function of the switch is faulty, or if
the switch is damaged, the entire switch unit must
be replaced.
OPERATION
The multi-function switch uses conventionally
switched outputs and a variable resistor to control
the many functions and features it provides using
hard wired circuitry. The switch is grounded at all
times through a single wire take out with an eyelet
terminal connector of the instrument panel wire har-
ness that is secured by a nut to a ground stud
located on the instrument panel armature, just above
and to the left of the glove box opening. When the
ignition switch is in the Accessory or On positions,
battery current from a fuse in the Junction Block
(JB) is provided through a fused ignition switch out-
put (run-acc) circuit. Following are descriptions of
how the multi-function switch operates to control the
many functions and features it provides:²Continuous Wipe Modes- When the control
knob of the multi-function switch is rotated to the
High or Low positions, the circuitry within the
switch provides a battery current output directly to
the high or low speed brush of the wiper motor.
When the control knob is in the Off position, the cir-
cuitry within the switch connects the output of the
wiper motor park switch to the low speed brush of
the wiper motor.
²Hazard Warning Control- The hazard warn-
ing push button is pushed down to unlatch the
switch and activate the hazard warning system, and
pushed down again to latch the switch and turn the
system off. When the hazard warning switch is
latched (hazard warning off), the push button will be
in a lowered position on the top of the steering col-
umn shroud; and, when the hazard warning switch is
unlatched (hazard warning on), the push button will
be in a raised position. The multi-function switch
hazard warning circuitry simultaneously provides a
signal to the hazard warning sense of the combina-
tion flasher to activate or deactivate the flasher out-
put, and directs the output of the flasher to the
hazard warning lamps.
²Headlamp Beam Selection- The multi-func-
tion switch control stalk is pulled towards the steer-
ing wheel past a detent, then released to actuate the
headlamp beam selection switch. Each time the con-
trol stalk is actuated in this manner, the opposite
headlamp mode from what is currently selected will
be activated. The internal circuitry of the headlamp
beam selection switch directs the output of the head-
lamp switch through hard wired circuitry to activate
the selected headlamp beam.
²Headlamp Optical Horn- The left multi-func-
tion switch control stalk is pulled towards the steer-
ing wheel to just before a detent, to momentarily
activate the headlamp high beams. The high beams
will remain illuminated until the control stalk is
released. The internal circuitry of the headlamp
beam selection switch provides a momentary ground
path to the headlamp high beams.
²Intermittent Wipe Mode- When the multi-
function switch control knob is rotated to the Delay
position, the circuitry within the switch connects the
output of the wiper motor relay to the low speed
brush of the wiper motor and provides a battery cur-
rent signal to the Central Timer Module (CTM). If
the Delay mode is selected, the control knob can then
be rotated to multiple minor detent positions, which
actuates a variable resistor within the switch and
provides a hard wired output to the CTM that sig-
nals the desired delay interval for the intermittent
wiper feature.
8L - 24 LAMPS/LIGHTING - EXTERIORBR/BE
MULTI-FUNCTION SWITCH (Continued)

(3) If the multi-function switch fails any of the
continuity or resistance tests, replace the faulty
switch unit as required.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) If the vehicle is so equipped, unscrew the lever
from the tilt steering column adjuster mechanism
located on the left side of the column just below the
multi-function switch control stalk. Turn the lever
counterclockwise to unscrew it from the adjuster.
(3) From below the steering column, remove the
two outboard screws that secure the upper shroud to
the lower outer shroud (Fig. 26).
(4) Press carefully inward on each side of the outer
shrouds to release the snap features and remove the
upper outer shroud from the lower outer shroud.
(5) From below the steering column, remove the
one center screw that secures the lower outer shroud
to the steering column housing.
(6) Remove the lower outer shroud from the steer-
ing column.
(7) From below the steering column, remove the
two screws that secure the lower inner shroud to the
steering column housing and the upper inner shroud.
(8) Press carefully inward on the gearshift lever
side of the inner shrouds to release the snap features
and remove the lower inner shroud from the steering
column.
(9) Carefully lift the upper inner shroud upward
far enough to access the multi-function switch
mounting screws.(10) Remove the two tamper proof screws (a Snap
On tamper proof Torx bit TTXR20B2 or equivalent is
required) that secure the multi-function switch to the
steering column housing.
(11) Gently pull the multi-function switch away
from the steering column far enough to access and
remove the screw that secures the instrument panel
wire harness connector for the multi-function switch
to the switch connector receptacle (Fig. 27).
(12) Disconnect the instrument panel wire harness
connector from the multi-function switch connector
receptacle.
(13) Remove the multi-function switch from the
steering column.
Fig. 26 Steering Column Shrouds Remove/Install -
Typical
1 - STEERING WHEEL
2 - TILT LEVER
3 - UPPER SHROUD
4 - PANEL BRACKET
5 - SPACER
6 - TOE PLATE
7 - NUT
8 - LOWER SHROUD
9 - CLOCK SPRING
10 - NUT
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 27
MULTI-FUNCTION SWITCH (Continued)

INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the multi-function switch next to the
steering column.
(2) Reconnect the instrument panel wire harness
connector for the multi-function switch to the switch
connector receptacle (Fig. 27).
(3) Install and tighten the screw that secures the
instrument panel wire harness connector for the
multi-function switch to the switch connector recep-
tacle. Tighten the screw to 2 N´m (18 in. lbs.).
(4) Position the multi-function switch onto the
steering column.(5) Carefully lift the upper inner shroud upward
far enough to access the multi-function switch
mounting screws.
(6) Install and tighten the two tamper proof
screws (a Snap On tamper proof Torx bit TTXR20B2
or equivalent is required) that secure the multi-func-
tion switch to the steering column housing. Tighten
the screws to 2 N´m (18 in. lbs.).
(7) Position the lower inner shroud onto the steer-
ing column (Fig. 26). Be certain to insert the gear-
shift lever hider strip into the channel located on the
inside surface of the shroud.
(8) Align the locking tabs on the gearshift lever
side of the upper inner shroud with the receptacles
on the lower inner shroud and apply hand pressure
to snap them together.
(9) From below the steering column, install and
tighten the two screws that secure the lower inner
shroud to the steering column housing and the upper
inner shroud. Tighten the screws to 2 N´m (18 in.
lbs.).
(10) Position the lower outer shroud onto the
steering column.
(11) From below the steering column, install and
tighten the one center screw that secures the lower
outer shroud to the steering column housing. Tighten
the screw to 2 N´m (18 in. lbs.).
(12) Align the locking tabs on the upper outer
shroud with the receptacles on the lower outer
shroud and apply hand pressure to snap them
together.
(13) From below the steering column, install and
tighten the two outboard screws that secure the
lower outer shroud to the upper outer shroud.
Tighten the screws to 2 N´m (18 in. lbs.).
(14) If the vehicle is so equipped, reinstall the
lever into the tilt steering column adjuster on the left
side of the column. Turn the lever clockwise to screw
it into the adjuster.
(15) Reconnect the battery negative cable.
OUTBOARD IDENTIFICATION
LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Using a flat blade screw driver, carefully pry
lamp to disengage clips attaching ID lamp to retainer
(Fig. 28).
(3) Separate ID lamp from retainer.
(4) Disengage lamp bulb socket from lamp.
(5) Remove screws attaching lamp retainer to rear
fender.
(6) Separate retainer from rear fender.
Fig. 27 Multi-Function Switch Connector
1 - WIRE HARNESS CONNECTORS
2 - SCREW
3 - WIRE HARNESS CONNECTOR
4 - MULTI-FUNCTION SWITCH
5 - WIRE HARNESS CONNECTOR
6 - CLOCKSPRING
7 - IGNITION SWITCH
8L - 28 LAMPS/LIGHTING - EXTERIORBR/BE
MULTI-FUNCTION SWITCH (Continued)

TURN SIGNAL CANCEL CAM
DESCRIPTION
The turn signal cancel cam is concealed within the
steering column below the steering wheel. The turn
signal cancel cam consists of two lobes that are inte-
gral to the lower surface of the clockspring rotor. The
clockspring mechanism provides turn signal cancella-
tion as well as a constant electrical connection
between the horn switch, driver airbag, speed control
switches, and remote radio switches on the steering
wheel and the instrument panel wire harness on the
steering column. The housing of the clockspring is
secured to the steering column and remains station-
ary. The rotor of the clockspring, including the turn
signal cancel cam lobes rotate with the steering
wheel.
The turn signal cancel cam is serviced as a unit
with the clockspring and cannot be repaired. If faulty
or damaged, the entire clockspring unit must be
replaced. (Refer to 8 - ELECTRICAL/RESTRAINTS/
CLOCKSPRING - REMOVAL).
OPERATION
The turn signal cancel cam has two lobes molded
into the lower surface of the clockspring rotor. When
the turn signals are activated by moving the multi-
function switch control stalk to a detent position, a
turn signal cancel actuator is extended from the
inside surface of the multi-function switch housing
toward the center of the steering column and the
turn signal cancel cam. When the steering wheel is
rotated during a turning maneuver, one of the two
turn signal cancel cam lobes will contact the turn sig-
nal cancel actuator. The cancel actuator latches
against the cancel cam rotation in the direction oppo-
site that which is signaled. In other words, if the left
turn signal detent is selected, the lobes of the cancel
cam will ratchet past the cancel actuator when the
steering wheel is rotated to the left, but will unlatch
the cancel actuator as the steering wheel rotates to
the right and returns to center, which will cancel the
turn signal event and release the control stalk from
the detent so it returns to the neutral Off position.
UNDERHOOD LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Insert a small flat blade in the access slot
between the lamp base and lamp lens.
(3) Pry the lamp lens upward and remove the
lamp lens (Fig. 31).
(4) Depress the bulb terminal inward (Fig. 32) to
release the bulb.
Fig. 30 Tail, Brake, Turn Signal and Back-up Lamp
Bulb
1 - TAIL LAMP
2 - SCREW
3 - LIGHTING HARNESS
4 - BULB
5 - RETAINING CLIP
6 - RETAINING STUDS
Fig. 31 Underhood Lamp Lens
1 - LAMP
2 - LAMP LENS
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 31
TAIL LAMP UNIT (Continued)

INSTALLATION
(1) Engage the replacement bulb wire loop to the
terminal closest to the lamp base wire connector.
(2) Depress the opposite terminal inward and
engage the remaining bulb wire loop.
(3) Position the lamp lens on the lamp base and
press into place.
(4) Connect the battery negative cable.
UNDERHOOD LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the wire harness connector from the
lamp.
(3) Remove lamp lens.
(4) Remove bulb.
(5) Remove screw attaching underhood lamp to the
inner hood panel (Fig. 33).
(6) Separate underhood lamp from vehicle.
INSTALLATION
(1) Install bulb.
(2) Install lamp lens.
(3) Position the underhood lamp on the hood inner
panel.
(4) Install the attaching screw through the lamp
and into the hood panel. Tighten the screw securely.
(5) Fold lamp housing over and firmly press onto
base to snap into place.
(6) Connect the wire harness connector to the
lamp.
(7) Connect the battery negative cable.
Fig. 32 Underhood Lamp Bulb
1 - BULB
2 - DEPRESS TERMINAL INWARD
3 - BULB WIRE LOOP
4 - LAMP BASE
Fig. 33 Underhood Lamp
1 - UNDER HOOD LAMP
2 - HOOD
3 - CONNECTOR
8L - 32 LAMPS/LIGHTING - EXTERIORBR/BE
UNDERHOOD LAMP (Continued)

DOME LAMP
REMOVAL
(1) Using a small flat blade, pry the left side (driv-
er's side) of the dome lamp lens downward from
dome lamp.
(2) Allow the lens to hang down (Fig. 1) , this will
disengage the right side of the lamp (passenger's
side) from the headliner.
(3) Pull the right side of the lamp down and slide
the lamp to the right (Fig. 2) .
(4) Separate the lamp from the headliner.
(5) Disengage dome lamp wire connector from body
wire harness.
(6) Separate dome lamp from vehicle.
INSTALLATION
(1) Position dome lamp at headliner.
(2) Connect dome lamp wire connector to body
wire harness.
(3) Position the left side of the lamp in the head-
liner opening and slide lamp to the left.
(4) Push the right side of the lamp in the head-
liner opening and push the lamp lens up into the
lamp to secure.
DOOR AJAR SWITCH
DESCRIPTION
The door ajar switches are mounted to the door
hinge pillars. The switches close a path to ground for
the Central Timer Module (CTM) when a door is
opened, and open the ground path when a door is
closed.
The door ajar switches cannot be repaired and, if
faulty or damaged, they must be replaced.
DIAGNOSIS AND TESTING - DOOR AJAR
SWITCH
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Rotate the headlamp switch knob counterclock-
wise to ensure that the dome lamps are not switched
off. Open the driver door and note whether the inte-
rior lamps light. They should light. If OK, (Refer to 8
- ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
HEADLAMP SWITCH - DIAGNOSIS AND TEST-
ING). If not OK, go to Step 2.
(2) Disconnect and isolate the battery negative
cable. Unplug the driver door ajar switch from its
wire harness connector. Check for continuity between
the ground circuit cavity of the driver door ajar
switch wire harness connector and a good ground.
There should be continuity. If OK, go to Step 3. If not
OK, repair the circuit to ground as required.
Fig. 1 Dome Lamp Lens
1 - HEADLINER
2 - CONNECTOR
3 - DOME LAMP
4 - LENS
5 - BULB
Fig. 2 Dome Lamp
1 - SLIDE LAMP
8L - 34 LAMPS/LIGHTING - INTERIORBR/BE

MESSAGE SYSTEMS
TABLE OF CONTENTS
page page
OVERHEAD CONSOLE
DESCRIPTION..........................1
STANDARD PROCEDURE
STANDARD PROCEDURE - COMPASS
CALIBRATION.........................4
STANDARD PROCEDURE - COMPASS
VARIATION ADJUSTMENT................4
STANDARD PROCEDURE - COMPASS
DEMAGNETIZING......................5
REMOVAL
OVERHEAD CONSOLE REMOVAL.........6
DISASSEMBLY
OVERHEAD CONSOLE DISASSEMBLY......7
ASSEMBLY
OVERHEAD CONSOLE ASSEMBLY........8
INSTALLATION
OVERHEAD CONSOLE INSTALLATION......8SPECIAL TOOLS
OVERHEAD CONSOLE SPECIAL TOOL.....9
COMPASS/MINI-TRIP COMPUTER
DESCRIPTION..........................9
OPERATION............................9
DIAGNOSIS AND TESTING - COMPASS
MINI-TRIP COMPUTER.................10
REMOVAL.............................11
INSTALLATION.........................11
AMBIENT TEMP SENSOR
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR...............12
REMOVAL.............................12
INSTALLATION.........................13
OVERHEAD CONSOLE
DESCRIPTION
Three different overhead console units are avail-
able factory-installed options on this model, base,
premium and premium with vehicle theft security.
The base overhead console unit features a garage
door opener storage bin, a sunglasses storage bin and
two reading and courtesy lamps. The premium over-
head console has all of the features of the base unit,
but adds a compass mini-trip computer and/or vehi-
cle theft security LED. See the owner's manual in
the vehicle glove box for more information on the fea-
tures, use and operation of all of the overhead con-
sole components and systems. Refer toOverhead
Consolein the Contents of Wiring Diagrams for
complete circuit diagrams.
The premium overhead console (Fig. 1) includes
two front-mounted reading and courtesy lamps, a
garage door opener storage bin, and a sunglasses
storage bin. The premium overhead console includesa compass mini-trip computer. The base overhead
console uses the same overhead console housing, but
has a computer cover plug installed in place of the
compass mini-trip computer display module lens and
push buttons.
The rear of the overhead console is secured to two
rear mounting holes in the inner roof panel by two
plastic hook formations that are integral to the over-
head console housing. The front of the overhead con-
sole is secured to the two front mounting holes of the
inner roof panel by two plastic latches that are inte-
gral to the overhead console housing. A single electri-
cal connection joins the overhead console wire
harness to the roof wire harness for both the base
and premium overhead console units.
Following are general descriptions of the major
components used in the overhead console. See the
owner's manual in the vehicle glove box for more
information on the use and operation of the various
overhead console features.
BR/BEMESSAGE SYSTEMS 8M - 1