2002 DODGE RAM ECU

(2) Use an ohmmeter to check the switch resis-
tances as shown in the Remote Radio Switch Test
chart. If the remote radio switch resistances check
OK, go to Step 3. If not OK, replace the faulty
switch.
REMOTE RADIO SWITCH TEST
SWITCH SWITCH POSITION RESISTANCE
Right
(White)Volume Up 7320 Ohms
Right
(White)Volume Down 1210 Ohms
Left
(Black)Seek Up 4530 Ohms
Left
(Black)Seek Down 2050 Ohms
Left
(Black)Pre-Set Station
Advance10 Ohms
(3) Check for continuity between the ground cir-
cuit cavity of the remote radio switch wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 4. If not OK, repair the open
ground circuit to ground as required.
(4) Disconnect the 18-way wire harness connector
from the Central Timer Module (CTM). Check for
continuity between the radio control mux circuit cav-
ity of the remote radio switch wire harness connector
and a good ground. There should be no continuity. If
OK, go to Step 5. If not OK, repair the shorted radio
control mux circuit as required.
(5) Check for continuity between the radio control
mux circuit cavities of the remote radio switch wire
harness connector and the 18-way CTM wire harness
connector. There should be continuity. If OK, refer to
the proper Diagnostic Procedures manual to test the
CTM and the Chrysler Collision Detection (CCD)
data bus. If not OK, repair the open radio control
mux circuit as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the driver side airbag module from the
steering wheel. Refer to Electrical, Restraints for the
procedures.
(3) Remove the speed control switch located on the
same side of the steering wheel as the remote radio
switch that is being serviced. Refer to Electrical,
Speed Control for the procedures.
(4) Disconnect the steering wheel wire harness
connector from the connector receptacle of the remote
radio switch (Fig. 17).(5) Disengage the four remote radio switch latches
that secure the switch to the inside of the mounting
hole in the steering wheel rear trim cover.
(6) From the outside of the steering wheel rear
trim cover, remove the remote radio switch from the
trim cover mounting hole.
INSTALLATION
(1) Position the remote radio switch to the mount-
ing hole on the outside of the steering wheel rear
trim cover. Be certain that the connector receptacle is
oriented toward the bottom of the switch and pointed
toward the center of the steering wheel.
(2) Press firmly and evenly on the remote radio
switch until each of the switch latches is fully
engaged in the mounting hole of the steering wheel
rear trim cover.
(3) Reconnect the steering wheel wire harness con-
nector to the connector receptacle of the remote radio
switch.
(4) Install the speed control switch onto the steer-
ing wheel. Refer to Electrical, Speed Control for the
procedures.
Fig. 17 Remote Radio Switches Remove/Install
1 - STEERING WHEEL
2 - REMOTE RADIO SWITCH
3 - SPEED CONTROL SWITCH
4 - SCREW (2)
5 - DRIVER SIDE AIRBAG MODULE
6 - SPEED CONTROL SWITCH
7 - REAR TRIM COVER
8 - SCREW (2)
8A - 16 AUDIOBR/BE
REMOTE SWITCHES (Continued)

(9) Remove the tweeter from the mounting hole in
the A-pillar trim.
INSTALLATION
(1) Position the tweeter into the mounting hole in
the A-pillar trim.
(2) Install the tweeter onto the A-pillar trim by
pushing in on the tweeter firmly and evenly from the
outside of the trim until it snaps into the mounting
hole.
(3) Use a suitable tape or adhesive to secure the
tweeter wire harness to the inside of the A-pillar
trim.
(4) Position the trim and tweeter to the A-pillar as
a unit.
(5) Reconnect the body wire harness connector to
the A-pillar tweeter wire harness connector.
(6) Engage the trim onto the A-pillar. Refer to
Body, Interior for the procedures.
(7) If the vehicle is so equipped, install the grab
handle onto the A-pillar. Refer to Body, Interior for
the procedures.
(8) Reconnect the battery negative cable.
FRONT DOOR SPEAKER
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the trim panel from the front door.
Refer to Body, Door Front for the procedures.
(3) Remove the four screws that secure the
speaker to the front door inner panel (Fig. 19).
(4) Pull the speaker away from the mounting hole
in the front door inner panel far enough to access the
speaker wire harness connector.
(5) Disconnect the speaker wire harness connector
from the front door wire harness connector.
(6) Remove the speaker from the front door inner
panel.
INSTALLATION
(1) Position the speaker to the front door inner
panel.
(2) Reconnect the speaker wire harness connector
to the front door wire harness connector.
(3) Position the speaker into the mounting hole in
the front door inner panel.
Fig. 18 A-Pillar Tweeter Remove/Install
1 - NUT
2 - WIRE HARNESS CONNECTOR
3 - MOULDING
4 - HANDLE
5 - PLUG
6 - SCREW
7 - TWEETER
Fig. 19 Front Door Speaker Remove/Install
1 - CLIP
2 - FRONT DOOR INNER PANEL
3 - WIRE HARNESS CONNECTOR
4 - SCREW
5 - SPEAKER
BR/BEAUDIO 8A - 19
A-PILLAR TWEETER SPEAKER (Continued)

(4) Install and tighten the four screws that secure
the speaker to the front door inner panel. Tighten
the screws to 4 N´m (35 in. lbs.).
(5) Install the trim panel onto the front door. Refer
to Body, Door Front for the procedures.
(6) Reconnect the battery negative cable.
REAR CAB SIDE PANEL
SPEAKER
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the trim from the rear cab side panel.
Refer to Body, Interior for the procedures.
(3) Remove the two screws that secure the speaker
to the cab side inner panel (Fig. 20) or (Fig. 21).
(4) Pull the speaker away from the mounting hole
in the cab side inner panel far enough to access the
body wire harness connector.
(5) Disconnect the body wire harness connector
from the speaker connector receptacle.
(6) Remove the speaker from the cab side inner
panel.
INSTALLATION
(1) Position the speaker to the cab side inner
panel.
(2) Reconnect the body wire harness connector to
the speaker connector receptacle.(3) Position the speaker into the mounting hole in
the cab side inner panel.
(4) Install and tighten the two screws that secure
the speaker to the cab side inner panel. Tighten the
screws to 4 N´m (35 in. lbs.).
(5) Install the trim onto the rear cab side panel.
Refer to Body, Interior for the procedures.
(6) Reconnect the battery negative cable.
REAR DOOR SPEAKER
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the trim panel from the rear door.
(3) Remove the two screws that secure the speaker
to the rear door inner panel (Fig. 22).
(4) Pull the speaker away from the mounting hole
in the rear door inner panel far enough to access the
door wire harness connector.
(5) Disconnect the door wire harness connector
from the speaker connector receptacle.
(6) Remove the speaker from the rear door inner
panel.
Fig. 20 Rear Speaker Remove/Install - Standard Cab
1 - CLIP
2 - SPEAKER
3 - SCREW
4 - WIRE HARNESS CONNECTOR
5 - CAB SIDE INNER PANEL
Fig. 21 Rear Speaker Remove/Install - Club Cab
1 - WIRE HARNESS CONNECTOR
2 - CAB SIDE INNER PANEL
3 - SPEAKER
4 - SCREW
5 - CLIP
8A - 20 AUDIOBR/BE
FRONT DOOR SPEAKER (Continued)

INSTALLATION
(1) Position the speaker to the rear door inner
panel.
(2) Reconnect the door wire harness connector to
the speaker connector receptacle.
(3) Position the speaker into the mounting hole in
the rear door inner panel.
(4) Install and tighten the two screws that secure
the speaker to the rear door inner panel. Tighten the
screws to 4 N´m (35 in. lbs.).
(5) Install the trim panel onto the rear door.
(6) Reconnect the battery negative cable.
Fig. 22 Rear Door Speaker Remove/Install - Quad
Cab
1 - REAR DOOR INNER PANEL
2 - WIRE HARNESS CONNECTOR
3 - SPEAKER
4 - SCREW
5 - CLIP
BR/BEAUDIO 8A - 21
REAR DOOR SPEAKER (Continued)

ELECTRONIC CONTROL MODULES
TABLE OF CONTENTS
page page
CENTRAL TIMER MODULE
DESCRIPTION..........................1
OPERATION............................3
DIAGNOSIS AND TESTING - CENTRAL TIMER
MODULE.............................4
REMOVAL.............................5
INSTALLATION..........................6
COMMUNICATION
DESCRIPTION - CCD DATA BUS............6
OPERATION - CCD DATA BUS..............7
DIAGNOSIS AND TESTING - CCD DATA BUS . . 11
CONTROLLER ANTILOCK BRAKE
DESCRIPTION.........................11
OPERATION...........................11
REMOVAL.............................11
INSTALLATION.........................12
DATA LINK CONNECTOR
DESCRIPTION - DATA LINK CONNECTOR....12
OPERATION - DATA LINK CONNECTOR......12
ENGINE CONTROL MODULE
DESCRIPTION - ECM....................13
OPERATION - ECM.....................13
REMOVAL.............................14
INSTALLATION.........................14POWERTRAIN CONTROL MODULE
DESCRIPTION
DESCRIPTION - PCM..................15
DESCRIPTION - MODES OF OPERATION . . . 15
DESCRIPTION - 5 VOLT SUPPLIES.......17
DESCRIPTION - IGNITION CIRCUIT SENSE . 17
DESCRIPTION - POWER GROUNDS......17
DESCRIPTION - SENSOR RETURN.......17
DESCRIPTION - SIGNAL GROUND........17
OPERATION
OPERATION - PCM - GAS ENGINES.......18
OPERATION - DIESEL..................18
OPERATION - 5 VOLT SUPPLIES.........19
OPERATION - IGNITION CIRCUIT SENSE . . . 19
REMOVAL.............................19
INSTALLATION.........................20
HEATED SEAT MODULE
DESCRIPTION.........................20
OPERATION...........................20
DIAGNOSIS AND TESTING - HEATED SEAT
MODULE............................21
REMOVAL.............................23
INSTALLATION.........................23
CENTRAL TIMER MODULE
DESCRIPTION
Three versions of the Central Timer Module (CTM)
are available on this vehicle, a base version (Fig. 1),
a high-line version (Fig. 2), and a premium version.
Whichever version of the CTM the vehicle is
equipped with, it is concealed under the driver side
end of the instrument panel inboard of the instru-
ment panel steering column opening, where it is
secured to a stamped steel bracket that is integral to
the instrument panel armature. The CTM is enclosed
in a molded plastic housing with one (base) or two
(high-line/premium) integral external connector
receptacles that connect it to the vehicle electrical
system through one (base) or two (high-line/pre-
mium) take outs with connectors from the instru-
ment panel wire harness.
The base version of the CTM is used on base mod-
els of this vehicle. It is also sometimes referred to as
the Integrated Electronic Module (IEM). The base
version of the CTM combines the functions of achime module and an intermittent wipe module in a
single unit. The high-line version of the CTM is used
on high-line vehicles. The high-line CTM provides all
of the functions of the base version of the CTM, but
also is used to control and integrate many additional
electronic functions and features included on high-
line models. The premium version of the CTM is the
same as the high-line version, but is used only on
models equipped with the heated seat option.
The high-line and premium versions of the CTM
utilize integrated circuitry and information carried
on the Chrysler Collision Detection (CCD) data bus
network along with many hard wired inputs to mon-
itor many sensor and switch inputs throughout the
vehicle. In response to those inputs, the internal cir-
cuitry and programming of the CTM allow it to con-
trol and integrate many electronic functions and
features of the vehicle through both hard wired out-
puts and the transmission of electronic message out-
puts to other electronic modules in the vehicle over
the CCD data bus.
BR/BEELECTRONIC CONTROL MODULES 8E - 1

CTM 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.
All versions of the CTM for this model are serviced
only as a complete unit. Many of the electronic fea-
tures in the vehicle controlled or supported by the
high-line or premium versions of the CTM are pro-
grammable using the DRBIIItscan tool.However, if
any of the CTM hardware components are damaged
or faulty, the entire CTM unit must be replaced. The
base version of the CTM and the hard wired inputs
or outputs of all CTM versions 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 appro-
priate diagnostic information.
OPERATION
The Central Timer Module (CTM) is designed to
control and integrate many of the electronic features
and functions of the vehicle. The base version of the
CTM monitors only hard wired inputs and responds
with the proper hard wired outputs. The microproces-
sor-based high-line/premium version of the CTM
monitors many hard wired switch and sensor inputs
as well as those resources it shares with other elec-
tronic modules in the vehicle through its communica-
tion over the Chrysler Collision Detection (CCD) data
bus network. The internal programming and all of
these inputs allow the high-line/premium CTM
microprocessor to determine the tasks it needs to
perform and their priorities, as well as both the stan-
dard and optional features that it should provide.
The high-line/premium CTM programming then per-
forms those tasks and provides those features
through both CCD data bus communication with
other electronic modules and through hard wired out-
puts to a number of circuits, relays, and actuators.
These outputs allow the high-line/premium CTM the
ability to control numerous accessory systems in the
vehicle.
All versions of the CTM operate on battery current
received through fuses in the Junction Block (JB) on
a non-switched fused B(+) circuit, a fused ignition
switch output (st-run) circuit (base version only), and
a fused ignition switch output (run-acc) circuit (high-
line/premium version only). This arrangement allows
the CTM to provide some features regardless of the
ignition switch position, while other features willoperate only with the ignition switch in the Acces-
sory, On, and/or Start positions. All versions of the
CTM are grounded through their connector and take
out of the instrument panel wire harness. The high-
line/premium CTM has another ground received
through a second connector and take out of the
instrument panel wire harness. The first ground cir-
cuit receives ground through a take out with an eye-
let terminal connector of the instrument panel wire
harness that is secured by a nut to a ground stud
located on the left instrument panel end bracket,
while the second ground circuit (high-line/premium
version only) receives ground through a take out with
an eyelet terminal connector of the instrument panel
wire harness that is secured by a nut to a ground
stud located on the back of the instrument panel
armature above the inboard side of the instrument
panel steering column opening.
The high-line/premium CTM monitors its own
internal circuitry as well as many of its input and
output circuits, and will store a Diagnostic Trouble
Code (DTC) in electronic memory for any failure it
detects. These DTCs can be retrieved and diagnosed
using a DRBIIItscan tool. Refer to the appropriate
diagnostic information.
HARD WIRED INPUTS
The hard wired inputs to the CTM include the fol-
lowing:
²CCD bus± - high-line/premium version only
²CCD bus+ - high-line/premium version only
²Cylinder lock switch mux - high-line premium
version only
²Driver door ajar switch sense
²Fused B(+)
²Fused ignition switch output (run-acc) - high-
line/premium version only
²Fused ignition switch output (st-run) - base ver-
sion only
²Ground (one circuit - base version, two circuits -
high-line/premium version)
²Key-in ignition switch sense
²Passenger door ajar switch sense - high-line/pre-
mium version only
²Power door lock motor B(+) lock - high-line/pre-
mium version only
²Power door lock motor B(+) unlock - high-line/
premium version only
²Radio control mux - high-line/premium version
only
²Tone request signal
²Washer switch sense
²Wiper park switch sense
²Wiper switch mode sense
²Wiper switch mode signal
BR/BEELECTRONIC CONTROL MODULES 8E - 3
CENTRAL TIMER MODULE (Continued)

(4) Turn the ignition switch to the On position. For
a base version CTM, check for battery voltage at the
fused ignition switch output (st-run) fuse (Fuse 11 -
10 ampere) in the JB. For a high-line/premium ver-
sion CTM, check for battery voltage at the fused igni-
tion switch output (run-acc) fuse (Fuse6-25
ampere) in the JB. If OK, go to Step 5. If not OK,
repair the shorted circuit or component as required
and replace the faulty fuse.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the CTM from its mounting bracket to access
the CTM wire harness connector(s). Disconnect the
instrument panel wire harness connector(s) for the
CTM from the CTM connector receptacle(s). Check
the wire harness connectors and the CTM receptacles
for loose, corroded, or damaged terminals and pins. If
OK, go to Step 6. If not OK, repair as required.
(6) Check for continuity between the ground cir-
cuit cavity of the instrument panel wire harness con-
nector (Connector C1) for the CTM and a good
ground. For the high-line/premium version of the
CTM only, repeat the check between the ground cir-
cuit cavity of the instrument panel wire harness con-
nector (Connector C2) for the CTM and a good
ground. In each case, there should be continuity. If
OK, go to Step 7. If not OK, repair the open ground
circuit(s) to ground as required.
(7) Reconnect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
instrument panel wire harness connector (Connector
C1) for the CTM. If OK, go to Step 8. If not OK,
repair the open fused B(+) circuit between the CTM
and the JB as required.
(8) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (st-run) circuit cavity (base version) or fused
ignition switch output (run-acc) circuit cavity (high-
line/premium version) of the instrument panel wire
harness connector (Connector C1) for the CTM. If OK
with a base version CTM, replace the faulty CTM. If
OK with a high-line/premium version CTM, use a
DRBIIItscan tool and the appropriate diagnostic
information to perform further diagnosis of the CTM.
If not OK, repair the open fused ignition switch out-
put circuit between the CTM and the JB.
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.
NOTE: Before replacing a high-line/premium version
Central Timer Module (CTM), use a DRBIIITscan
tool to retrieve the current settings for the CTM pro-
grammable features. Refer to the appropriate diag-
nostic information. These settings should be
duplicated in the replacement high-line/premium
CTM using the DRBIIITscan tool before returning
the vehicle to service.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the steering column opening cover
from the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).
(3) Remove the two screws that secure the Central
Timer Module (CTM) to the bracket on the inboard
side of the instrument panel steering column opening
(Fig. 3) or (Fig. 4).
(4) Pull the CTM into the instrument panel steer-
ing column opening far enough to access the instru-
ment panel wire harness connector(s).
Fig. 3 Central Timer Module (Base) Remove/Install
1 - SCREWS
2 - BRACKET
3 - WIRE HARNESS CONNECTOR
4 - CENTRAL TIMER MODULE
BR/BEELECTRONIC CONTROL MODULES 8E - 5
CENTRAL TIMER MODULE (Continued)

(5) Disconnect the instrument panel wire harness
connector(s) (one connector for the base version CTM,
two connectors for the high-line/premium version)
from the CTM connector receptacle(s).
(6) Remove the CTM from the instrument panel.
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.
NOTE: Before replacing a high-line/premium version
Central Timer Module (CTM), use a DRBIIITscan
tool to retrieve the current settings for the CTM pro-
grammable features. Refer to the appropriate diag-
nostic information. These settings should be
duplicated in the replacement high-line/premiumCTM using the DRBIIITscan tool before returning
the vehicle to service.
(1) Position the CTM to the inboard side of the
instrument panel steering column opening.
(2) Reconnect the instrument panel wire harness
connector(s) for the CTM (one connector for the base
version CTM, two connectors for the high-line/pre-
mium version) to the CTM connector receptacle(s)
(Fig. 3) or (Fig. 4).
(3) Position the CTM to the bracket on the inboard
side of the instrument panel steering column open-
ing.
(4) Install and tighten the two screws that secure
the CTM to the bracket on the inboard side of instru-
ment panel steering column opening. Tighten the
screws to 1.6 N´m (15 in. lbs.).
(5) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(6) Reconnect the battery negative cable.
COMMUNICATION
DESCRIPTION - CCD DATA BUS
The Chrysler Collision Detection (also referred to as
CCD or CD) data bus system is a multiplex system
used for vehicle communications on many
DaimlerChrysler Corporation vehicles. Within the con-
text of the CCD system, the term ªcollisionª refers to
the system's ability to avoid collisions of the electronic
data that enters the data bus from various electronic
control modules at approximately the same time.
Multiplexing is a system that enables the trans-
mission of several messages over a single channel or
circuit. Many DaimlerChrysler vehicles use this prin-
ciple for communication between the various micro-
processor-based electronic control modules.
Many of the electronic control modules in a vehicle
require information from the same sensing device. In
the past, if information from one sensing device was
required by several controllers, a wire from each con-
troller needed to be connected in parallel to that sen-
sor. In addition, each controller utilizing analog
sensors required an Analog/Digital (A/D) converter in
order to ªreadª these sensor inputs. Multiplexing
reduces wire harness complexity, sensor current
loads and controller hardware because each sensing
device is connected to only one controller, which
reads and distributes the sensor information to the
other controllers over the data bus. Also, because
each controller on the data bus can access the con-
troller sensor inputs to every other controller on the
data bus, more function and feature capabilities are
possible.
Fig. 4 Central Timer Module (High-Line/Premium)
Remove/Install
1 - SCREWS
2 - BRACKET
3 - WIRE HARNESS CONNECTORS
4 - CENTRAL TIMER MODULE
8E - 6 ELECTRONIC CONTROL MODULESBR/BE
CENTRAL TIMER MODULE (Continued)