wiring DODGE RAM 2002 Service Manual Online

CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMP SWITCH OFF
HEADLAMPS AND
HIGHBEAM INDICATOR
REMAIN ON AND ARE
DIM.1. Headlamp switch feed circuit
shorted to ground.1. Check wiring circuit from right headlamp
fuse to headlamp. Repeat for left side.
Trace short circuit in wiring and repair.
HEADLAMP SWITCH ON
(LOW BEAMS ON), ONE
LOW BEAM ON AND
BOTH HIGH BEAMS DIM.1. Headlamp feed circuit shorted to
ground.1. Check wiring circuit from right headlamp
fuse to headlamp. Repeat for left side.
Trace short circuit in wiring and repair.
HEADLAMP SWITCH ON
(HIGH BEAMS ON), ONE
HIGH BEAM ON AND
BOTH LOW BEAMS DIM.1. Headlamp feed circuit shorted to
ground.1. Check wiring circuit from right headlamp
fuse to headlamp. Repeat for left side.
Trace short circuit in wiring and repair.
HEADLAMP SWITCH ON,
ONE HEADLAMP
FILAMENT WILL BE AT
FULL INTENSITY AND ALL
OTHER FILAMENTS ARE
ON AND DIM.1. Blown headlamp fuse. 1. Trace short circuit and replace fuse.
2. Open circuit from headlamp fuse
to headlamp.2. Repair open headlamp circuit.
1. HEADLAMPS STAY ON
WITH KEY OUT (DRLM
EQUIPPED VEHICLES).1. Failed DRLM 1. Replace DRLM.
*Canada vehicles must have lamps ON.
REMOVAL
On the driver side, the battery and battery tray
must be removed to service the headlamp bulb.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the battery tray (Refer to 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - REMOVAL).
(3) Disengage wire connector from headlamp
bulb(s).
(4) Remove retaining ring holding bulb(s) to head-
lamp (Fig. 13).
(5) Pull bulb(s) from headlamp.
INSTALLATION
CAUTION: Do not touch the bulb glass with fingers
or other oily surfaces. Reduced bulb life will result.
(1) Position bulb(s) in headlamp.
(2) Install retaining ring holding bulb(s) to head-
lamp.
(3) Connect wire connector to headlamp bulb(s).(4) Install battery tray, if removed (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/TRAY - INSTAL-
LATION).
(5) Connect battery negative cable.
Fig. 13 Headlamp Bulb
1 - BULB SOCKET
2 - BULB ASSEMBLY
3 - LOCK
4 - BULB RETAINING RING
5 - ELECTRICAL CONNECTOR
6 - UNLOCK
7 - PLASTIC BASE
8L - 16 LAMPS/LIGHTING - EXTERIORBR/BE
HEADLAMP (Continued)

the PDC cover for headlamp relay identification and
location. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, details
of wire harness routing and retention, connector pin-
out information and location views for the various
wire harness connectors, splices and grounds.
(1) Remove the headlamp relay from the PDC.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/HEADLAMP RELAY - REMOVAL).
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, test the relay input and output cir-
cuits. If not OK, replace the faulty relay.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Unlatch and remove the cover from the Power
Distribution Center (PDC) (Fig. 16).
(3) See the fuse and relay layout label affixed to
the underside of the PDC cover for headlamp (or
security) relay identification and location.
(4) Remove the headlamp relay by grasping it
firmly and pulling it straight out from the receptacle
in the PDC.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the PDC cover for the proper head-
lamp (or security) relay location.
(2) Position the headlamp relay in the proper
receptacle in the PDC.
(3) Align the headlamp relay terminals with the
terminal cavities in the PDC receptacle.
(4) Push firmly and evenly on the top of the head-
lamp relay until the terminals are fully seated in the
terminal cavities in the PDC receptacle.
(5) Reinstall and latch the cover onto the PDC.
(6) Connect the battery negative cable.
HEADLAMP SWITCH
DESCRIPTION
The headlamp switch module is located on the
instrument panel. The headlamp switch controls the
parking lamps, and the headlamps. A separate switch
in the module controls the interior lamps and instru-
ment cluster illumination. This switch also contains
a rheostat for controlling the illumination level of the
cluster lamps.
OPERATION
The headlamp switch has an off position, a parking
lamp position, and a headlamp on position. High
beams are controlled by the multifunction switch on
the steering column. The headlamp switch cannot be
repaired. It must be replaced.
Fig. 15 Headlamp Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
Fig. 16 Power Distribution Center
1 - COVER
2 - POWER DISTRIBUTION CENTER
8L - 18 LAMPS/LIGHTING - EXTERIORBR/BE
HEADLAMP RELAY (Continued)

DIAGNOSIS AND TESTING - HEADLAMP
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) Disconnect and isolate the battery negative
cable. Remove the headlamp switch from the instru-
ment panel. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/HEADLAMP SWITCH -
REMOVAL) for the procedures. Unplug the headlamp
switch wire harness connectors. Check for continuity
between the left door jamb switch sense circuit cavity
of the headlamp switch wire harness connector and a
good ground. There should be continuity with the
driver door open, and no continuity with the driver
door closed. If OK, go to Step 2. If not OK, repair the
circuit to the driver door jamb switch as required.
(2) Remove the Central Timer Module (CTM) from
its mounting bracket to access the CTM wire harness
connectors. (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/BODY CONTROL/
CENTRAL TIMER MODUL - REMOVAL) for the
procedures. Unplug the 14-way CTM wire harness
connector. Remove the key from the ignition lock cyl-
inder. Check for continuity between the key-in igni-
tion switch sense circuit cavity of the 14-way CTM
wire harness connector and a good ground. There
should be no continuity. If OK, go to Step 3. If not
OK, repair the short circuit as required.
(3) Check for continuity between the key-in igni-
tion switch sense circuit cavities of the 14-way CTM
wire harness connector and the headlamp switch
wire harness connector. There should be continuity. If
OK, go to Step 4. If not OK, repair the open circuit
as required.
(4) Check for continuity between the left front door
jamb switch sense circuit terminal and the key-in
ignition switch sense circuit terminal of the head-
lamp switch. There should be no continuity with the
switch in the Off position, and continuity with the
switch in the park or head lamps On position. If
OK,(Refer to 8 - ELECTRICAL/ELECTRONIC CON-TROL MODULES/BODY CONTROL/CENTRAL
TIMER MODUL - DIAGNOSIS AND TESTING) If
not OK, replace the faulty headlamp switch.
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) Remove the cluster bezel from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - REMOVAL).
(3) Remove the three screws that secure the head-
lamp switch to the instrument panel (Fig. 17).
Fig. 17 Headlamp Switch Removal
1 - SCREWS (3)
2 - HEADLAMP SWITCH
3 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 19
HEADLAMP SWITCH (Continued)

²Turn Signal Control- The multi-function
switch control stalk actuates the turn signal switch.
When the control stalk is moved in the upward direc-
tion, the right turn signal circuitry is activated; and,
when the control stalk is moved in the downward
direction, the left turn signal circuitry is activated.
The multi-function switch turn signal circuitry simul-
taneously provides a signal to the turn signal sense
of the combination flasher to activate or deactivate
the flasher output, and directs the output of the
flasher to the proper turn signal lamps. The turn sig-
nal switch has a detent position in each direction
that provides turn signals with automatic cancella-
tion, and an intermediate, momentary position in
each direction that provides turn signals only until
the multi-function switch control stalk is released.
When the control stalk is moved to a turn signal
switch detent position, the cancel actuator extends
toward the center of the steering column. A turn sig-
nal cancel cam that is integral to the clockspring
mechanism rotates with the steering wheel and the
cam lobes contact the cancel actuator when it is
extended from the multi-function switch. When the
steering wheel is rotated during a turning maneuver,
one of the two turn signal cancel cam lobes will con-
tact the turn signal cancel actuator. The cancel
actuator latches against the cancel cam rotation in
the direction opposite 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 steer-
ing 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.
²Washer Mode- Pushing the button on the end
of the multi-function switch control knob towards the
steering column provides a battery current output
through the momentary single pole, single throw
washer switch circuitry to operate the washer pump/
motor and provides a signal to the CTM. If the wip-
ers are not operating when the washer switch is
actuated, the CTM will operate the wiper motor for
as long as the washer switch is depressed plus about
three additional wipe cycles. If the wipers are oper-
ating in the intermittent mode when the washer
switch is actuated, the CTM will operate the wiper
motor at a fixed low speed for as long as the washer
switch is depressed plus about three additional wipe
cycles before the wipers return to the selected inter-
mittent wipe interval.DIAGNOSIS AND TESTING - MULTI-FUNCTION
SWITCH
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
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. Disconnect the instrument panel wire harness
connector from the multi-function switch connector
receptacle.
(2) Using an ohmmeter, perform the continuity
and resistance tests at the terminals in the multi-
function switch connector receptacle as shown in the
Multi-Function Switch Tests chart (Fig. 25).
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 25
MULTI-FUNCTION SWITCH (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

(5) Reach through the glove box opening and
behind the glove box lamp and switch mounting
bracket to depress the retaining tabs on the top and
bottom of the glove box lamp and switch housing.
(6) While holding the retaining tabs depressed,
push the glove box lamp and switch unit out through
the hole in the mounting bracket on the instrument
panel glove box opening upper reinforcement.
(7) Remove the glove box lamp and switch unit
from the instrument panel.
INSTALLATION
(1) Reach through the glove box opening and
behind the glove box lamp and switch mounting
bracket to feed the instrument panel wire harness
connectors out through the hole in the glove box
lamp and switch housing mounting bracket.
(2) Position the glove box lamp and switch unit to
the instrument panel.
(3) Reconnect the instrument panel wire harness
connector to the connector receptacle on the back of
the glove box lamp and switch unit.
(4) Push the glove box lamp and switch unit into
the hole in the mounting bracket on the instrument
panel glove box opening upper reinforcement.
(5) Install the glove box onto the instrument panel.
(Refer to 23 - BODY/INSTRUMENT PANEL/GLOVE
BOX - INSTALLATION) for the procedures.
(6) Close the glove box.
(7) Reconnect the battery negative cable.
READING LAMP
DESCRIPTION
The overhead console in this vehicle is equipped
with two individual reading and courtesy lamps. The
lamp lenses are the only visible components of these
lamps. The reading and courtesy lamp lenses are
mounted in the overhead console housing between
the garage door opener storage bin and the sun-
glasses storage bin. Each lamp has its own switch,
bulb, reflector and lens; but both lamps share a com-
mon lamp housing within the overhead console.
The overhead console reading and courtesy lamps
operate on battery current that is provided at all
times, regardless of the ignition switch position. The
ground feed for the lamps is switched through the
integral reading and courtesy lamp switches or
through the door jamb switches. Each lamp is
designed and aimed to provide illumination that will
be directed only to that side of the vehicle on which
the lamp is located.The reading and courtesy lamp lenses, bulbs and
the lamp housing and reflector unit are available for
service replacement. The reading and courtesy lamp
switches, bulb holders and wiring are only available
as part of the overhead console wire harness. If
either of the lamp switches or bulb holders is faulty
or damaged, the entire overhead console wire har-
ness assembly must be replaced.
For service of the reading and courtesy lamp bulbs,
refer to the appropriate wiring information. The wir-
ing information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
OPERATION
All reading and courtesy lamps located in the over-
head console are activated by the door jamb switches.
When all of the doors are closed, these lamps can be
individually activated by depressing the correspond-
ing lens. When any door is open, depressing the lamp
lenses to activate the lamp switches will not turn the
lamps off.
See the owner's manual in the vehicle glove box for
more information on the use and operation of the
overhead console reading and courtesy lamps.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Insert a long, narrow, flat-bladed tool between
the curved (outboard) edge of the reading and cour-
tesy lamp lens and the overhead console housing
(Fig. 5).
(3) Gently pry inward and downward against the
lens until the latch tab in the center of the outboard
edge of the reading and courtesy lamp lens is disen-
gaged from the overhead console housing.
(4) Pull firmly on the lens toward the outboard
side of the vehicle to disengage the two pivot tabs on
the inboard edge of the reading and courtesy lamp
lens are disengaged from the overhead console hous-
ing.
(5) Remove the reading and courtesy lamp lens
from the overhead console housing.
8L - 36 LAMPS/LIGHTING - INTERIORBR/BE
GLOVE BOX LAMP AND SWITCH (Continued)

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

will return to the last function being displayed before
the ignition was turned to the Off position. With the
ignition switch in the On position, momentarily
depressing and releasing the Step push button switch
will cause the compass-mini-trip computer to change
its mode of operation, and momentarily depressing
and releasing the U.S./Metric push button will cause
the unit to toggle between U.S. and Metric measure-
ments. While in either compass mode, depressing the
U.S./Metric push button for more than ten seconds
will toggle the display between the compass/temper-
ature and the compass/compass in degrees modes.
This compass mini-trip computer features several
functions that can be reset. If both the Step and U.S./
Metric push buttons are depressed at the same time
with the ignition switch in the On position, the trip
computer information that can be reset is reset.
Depressing and releasing the Step and U.S./Metric
push buttons at the same time for more than 100
milliseconds, but not more than one second while in
any display mode (except the compass/temperature
mode) will cause a local reset. A local reset affects
only the function currently displayed. See the Reset
Chart below for more information on this feature.
Performing a local reset while in the compass/tem-
perature mode enters the module into the compass
variance setting mode.
Depressing and releasing the Step and U.S./Metric
push buttons at the same time for more than two
seconds while in any display mode (except the com-
pass/temperature mode) will cause a global reset. A
global reset changes all of the trip computer func-
tions that can be reset.
For more information on the features and control
functions of the compass mini-trip computer, see the
owner's manual in the vehicle glove box.
DIAGNOSIS AND TESTING - COMPASS
MINI-TRIP COMPUTER
If the problem with the compass mini-trip com-
puter module is an inoperative security indicator
lamp, refer toSecurity Indicator Lampin Vehicle
Theft/Security Systems. If the problem with the com-
pass mini-trip computer module is an ªOCº or ªSCº in
the compass/thermometer display, refer toAmbient
Temperature Sensorin this section. If the problem
with the compass mini-trip computer module is an
inaccurate or scrambled display, refer toCMTC Self-
Diagnostic Testin this section. If the problem with
the compass mini-trip computer module is incorrect
Vacuum Fluorescent Display (VFD) dimming levels,
use a DRBtscan tool and the proper Diagnostic Pro-
cedures manual to test for the correct dimming mes-
sage inputs being received from the instrument
cluster over the Chrysler Collision Detection (CCD)
data bus. If the problem is a no-display condition,use the following procedures. For complete circuit
diagrams, refer toOverhead Consolein the Con-
tents of Wiring Diagrams.
(1) Check the fused B(+) fuse in the junction block.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the battery as
required.
(3) Check the fused ignition switch output (run/
start) fuse in the junction block. If OK, go to Step 4.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the junction block. If OK,
go to Step 5. If not OK, repair the open fused ignition
switch output (run/start) circuit to the ignition switch
as required.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the overhead console. Check for continuity
between the ground circuit cavities of the roof wire
harness connector for the overhead console and a
good ground. There should be continuity. If OK, go to
Step 6. If not OK, repair the open ground circuit to
ground as required.
(6) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
roof wire harness connector for the overhead console.
If OK, go to Step 7. If not OK, repair the open fused
B(+) circuit to the junction block fuse as required.
(7) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) circuit cavity of the roof wire har-
ness connector for the overhead console. If OK, refer
toSelf-Diagnostic Testin the Diagnosis and Test-
ing section of this group for further diagnosis of the
compass mini-trip computer module and the CCD
data bus. If not OK, repair the open fused ignition
switch output (run/start) circuit to the junction block
fuse as required.
CMTC SELF-DIAGNOSTIC TEST
A self-diagnostic test is used to determine that the
compass mini-trip computer module is operating
properly electrically. Initiate the self-diagnostic test
as follows:
(1) With the ignition switch in the Off position,
simultaneously depress and hold the Step button and
the U.S./Metric button.
(2) Turn the ignition switch to the On position.
(3) Continue to hold both buttons depressed until
the compass mini-trip computer module enters the
8M - 10 MESSAGE SYSTEMSBR/BE
COMPASS/MINI-TRIP COMPUTER (Continued)

AMBIENT TEMP SENSOR
DESCRIPTION
Ambient air temperature is monitored by the com-
pass mini-trip computer module through the ambient
temperature sensor. The ambient temperature sensor
is a variable resistor mounted to a bracket that is
secured with a screw to the underside of the hood
panel near the hood latch striker in the engine com-
partment (Fig. 8).
For complete circuit diagrams, refer toOverhead
Consolein the Contents of Wiring Diagrams. The
ambient temperature sensor cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
The ambient temperature sensor is a variable
resistor that operates on a five-volt reference signal
sent to it by the compass mini-trip computer module.
The resistance in the sensor changes as temperature
changes, changing the return circuit voltage to the
compass mini-trip computer module. Based upon the
resistance in the sensor, the compass mini-trip com-
puter module senses a specific voltage on the return
circuit, which it is programmed to correspond to a
specific temperature.
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR
The thermometer function is supported by the
ambient temperature sensor, a wiring circuit, and a
portion of the compass mini-trip computer module. If
any portion of the ambient temperature sensor cir-
cuit fails, the compass/thermometer display function
will self-diagnose the circuit. If 55É C (131É F)
appears in the display, the sensor is being exposed to
temperatures above 55É C (131É F), or the sensor cir-
cuit is shorted. If ±40É C (±40É F) appears in the dis-
play, the sensor is being exposed to temperatures
below ±40É C (±40É F), or the sensor circuit is open.
The ambient temperature sensor circuit can also be
diagnosed using the following Sensor Test, and Sen-
sor Circuit Test. If the temperature sensor and cir-
cuit are confirmed to be OK, but the temperature
display is inoperative or incorrect, refer toDiagnosis
and Testing the Compass Mini-Trip Computer.
For complete circuit diagrams, refer toWiring Dia-
grams.
SENSOR TEST
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire har-
ness connector.(2) Measure the resistance of the ambient temper-
ature sensor. At ±40É C (±40É F), the sensor resis-
tance is 336 kilohms. At 55É C (131É F), the sensor
resistance is 2.488 kilohms. The sensor resistance
should read between these two values. If OK, refer to
theSensor Circuit Test below. If not OK, replace
the faulty ambient temperature sensor.
SENSOR CIRCUIT TEST
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire har-
ness connector and the overhead console wire har-
ness connector.
(2) Connect a jumper wire between the two termi-
nals in the body half of the ambient temperature sen-
sor wire harness connector.
(3) Check for continuity between the sensor return
circuit and the ambient temperature sensor signal
circuit cavities of the roof wire harness overhead con-
sole connector. There should be continuity. If OK, go
to Step 4. If not OK, repair the open sensor return
circuit or ambient temperature sensor signal circuit
to the ambient temperature sensor as required.
(4) Remove the jumper wire from the body half of
the ambient temperature sensor wire harness con-
nector. Check for continuity between the sensor
return circuit cavity of the roof wire harness over-
head console connector and a good ground. There
should be no continuity. If OK, go to Step 5. If not
OK, repair the shorted sensor return circuit as
required.
(5) Check for continuity between the ambient tem-
perature sensor signal circuit cavity of the roof wire
harness overhead console connector and a good
ground. There should be no continuity. If OK, refer to
Diagnosis and Testing the Compass Mini-Trip
Computerin this section. If not OK, repair the
shorted ambient temperature sensor signal circuit as
required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Locate the ambient temperature sensor, on the
underside of the hood near the hood latch striker
(Fig. 8).
(3) Disconnect the wire harness connector from the
ambient temperature sensor connector receptacle.
(4) Remove the one screw that secures the ambient
temperature sensor bracket to the inner hood rein-
forcement.
(5) Remove the ambient temperature sensor from
the inner hood reinforcement.
8M - 12 MESSAGE SYSTEMSBR/BE

Both versions of the power lock system include the
following major components, which are described in
further detail elsewhere in this service manual:
²Power Lock Motors- A reversible electric
motor integral to the door latch of each front door
locks or unlocks the front door latch when provided
with the appropriate electrical inputs.
²Power Lock Switches- A power lock switch
integral to the power window/lock switch unit located
near the forward end of the arm rest on each front
door trim panel allows the power door lock system to
be operated by either the driver or the front seat pas-
senger.
On those models equipped with the optional RKE
system, the power lock system also includes the fol-
lowing components, which are described in further
detail elsewhere in this service manual:
²Central Timer Module- The high-line or pre-
mium Central Timer Module (CTM) is located under
the driver side end of the instrument panel, inboard
of the instrument panel steering column opening.
The high-line or premium CTM contains a micropro-
cessor and software that allow it to provide the many
electronic functions and features not available with
base version of the power lock system.
²Door Cylinder Lock Switches- A resistor-
multiplexed switch located on the back of each front
door lock cylinder allows the power door lock system
to be operated using a key inserted in either the
driver or passenger front door lock cylinder.
Some of the additional features of the power lock
system found in vehicles with the RKE system option
include:
²Automatic Door Lock- The high-line/premium
CTM provides an optional automatic door lock fea-
ture (also known as rolling door locks). This is a pro-
grammable feature.
²Central Locking- The high-line/premium CTM
provides an optional central locking/unlocking fea-
ture.
²Door Lock Inhibit- The high-line/premium
CTM provides a door lock inhibit feature.
²Enhanced Accident Response- The high-line/
premium CTM provides an optional enhanced acci-
dent response feature. This is a programmable
feature.
Hard wired circuitry connects the power lock sys-
tem components to the electrical system of the vehi-
cle. 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 connected to each other, to the
vehicle electrical system and to the power lock sys-
tem components through the use of a combination of
soldered splices, splice block connectors, and many
different types of wire harness terminal connectorsand insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
Many of the electronic features in the vehicle con-
trolled or supported by the high-line or premium ver-
sions of the CTM are programmable using the
DRBIIItscan tool. In addition, the high-line/pre-
mium CTM software is Flash compatible, which
means it can be reprogrammed using Flash repro-
gramming procedures. However, if any of the CTM
hardware components are damaged or faulty, the
entire CTM unit must be replaced. The power lock
system components and the hard wired inputs or out-
puts of the CTM can be diagnosed using conventional
diagnostic tools and methods; however, for diagnosis
of the high-line or premium versions of the CTM or
the CCD data bus, the use of a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
DESCRIPTION - REMOTE KEYLESS ENTRY
SYSTEM
A Remote Keyless Entry (RKE) system is an avail-
able option on this model. The Remote Keyless Entry
(RKE) system is a Radio Frequency (RF) system that
allows the remote operation of the power lock system
and, if the vehicle is so equipped, the Vehicle Theft
Security System (VTSS). (Refer to 8 - ELECTRICAL/
VEHICLE THEFT SECURITY - DESCRIPTION).
The RKE system includes the following major compo-
nents, which are described in further detail else-
where in this service manual:
²Central Timer Module- The high-line or pre-
mium Central Timer Module (CTM) is located under
the driver side end of the instrument panel, inboard
of the instrument panel steering column opening.
The high-line or premium CTM contains a micropro-
cessor, an RF receiver, and the software that allow it
to provide the many electronic functions and features
of the RKE system.
²Keyless Entry Transmitter- The keyless
entry transmitter is a small, battery-powered, RF
transmitter that is contained within a molded plastic
case that is designed to also serve as a convenient
key fob.
Some additional features of the RKE system
include:
²Horn Chirp- This feature provides a short,
sharp chirp of the vehicle horn to give an audible
confirmation that a valid Lock signal has been
received from the RKE transmitter. This feature can
be enabled or disabled and, if enabled, one of two
8N - 2 POWER LOCKSBR/BE
POWER LOCKS (Continued)