2001 DODGE RAM central timer module

external connector receptacles that connect it to the
vehicle electrical system through one (base) or two
(high-line/premium) take outs with connectors from
the instrument 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 a
chime 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.
The features that the CTM supports or controls
include the following:
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.
²Chimes- All versions of the CTM provide chime
service through an integral chime tone generator.
²Courtesy Lamps- The high-line/premium CTM
provides courtesy lamp control with timed load shed-
ding.
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.
²Heated Seats- The premium CTM controls the
optional heated seat system by controlling the opera-
tion of the heated seat relay.
²Illuminated Entry- The high-line/premium
CTM provides a timed illuminated entry feature.²Intermittent Wipe Control- All versions of
the CTM provide control of the intermittent wipe
delay, and wipe-after-wash features.
²Panic Mode- The high-line/premium CTM pro-
vides support for the optional RKE system panic
mode features.
²Power Lock Control- The high-line/premium
CTM provides the optional power lock system fea-
tures, including support for the automatic door lock
and door lock inhibit modes.
²Programmable Features- The high-line/pre-
mium CTM provides support for certain programma-
ble features.
²Remote Keyless Entry- The high-line/pre-
mium CTM provides the optional Remote Keyless
Entry (RKE) system features, including support for
the RKE Lock (with optional horn chirp), Unlock,
Panic, and illuminated entry modes, as well as the
ability to be programmed to recognize up to four
RKE transmitters. The RKE horn chirp is a program-
mable feature.
²Remote Radio Switch Interface- The high-
line/premium CTM monitors and transmits the sta-
tus of the optional remote radio switches.
²Speed Sensitive Intermittent Wipe Control-
The high-line/premium CTM provides the speed sen-
sitive intermittent wipe feature.
²Vehicle Theft Alarm- The high-line/premium
CTM provides control of the optional Vehicle Theft
Alarm features, including support for the central
locking/unlocking mode.
Hard wired circuitry connects the CTM to the elec-
trical 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 connected to
each other, to the vehicle electrical system and to the
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. In addition,
the high-line/premium CTM software is Flash com-
patible, which means it can be reprogrammed using
Flash reprogramming procedures. However, if any of
the CTM hardware components are damaged or
faulty, the entire CTM unit must be replaced. The
8E - 2 ELECTRONIC CONTROL MODULESBR/BE
BODY CONTROL/CENTRAL TIMER MODULE (Continued)

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 will
operate 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 panelarmature 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
HARD WIRED OUTPUTS
The hard wired outputs of the CTM include the fol-
lowing:
²CCD bus± - high-line/premium version only
²CCD bus+ - high-line/premium version only
²Courtesy lamp switch output - high-line/pre-
mium version only
²Door lock driver - high-line/premium version
only
²Door unlock driver - high-line/premium version
only
²Headlamp relay control - high-line/premium ver-
sion only
²Heated seat relay control - premium version
only
BR/BEELECTRONIC CONTROL MODULES 8E - 3
BODY CONTROL/CENTRAL TIMER MODULE (Continued)

²Horn relay control - high-line/premium version
only
²VTSS indicator driver - high-line/premium ver-
sion only
²Wiper motor relay control
MESSAGING
The high-line/premium CTM uses the following
messages received from other electronic modules over
the CCD data bus:
²Airbag Deploy (ACM)
²Charging System Failure (PCM)
²Engine RPM (PCM)
²System Voltage (PCM)
²Vehicle Speed (PCM)
²Voltage Fault (PCM)
The high-line/premium CTM provides the following
messages to other electronic modules over the CCD
data bus:
²Engine Enable (PCM)
²Radio Seek Up (Radio)
²Radio Seek Down (Radio)
²Radio Volume Up (Radio)
²Radio Volume Down (Radio)
²Preset Scan (Radio)
DIAGNOSIS AND TESTING - CENTRAL TIMER
MODULE
The hard wired inputs to and outputs from the
Central Timer Module (CTM) may be diagnosed and
tested using conventional diagnostic tools and meth-
ods. 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 har-
ness connectors, splices and grounds.
However, conventional diagnostic methods may not
prove conclusive in the diagnosis of the high-line/pre-
mium CTM. In order to obtain conclusive testing of
the high-line/premium CTM, the Chrysler Collision
Detection (CCD) data bus network and all of the elec-
tronic modules that provide inputs to or receive out-
puts from the CTM must also be checked. The most
reliable, efficient, and accurate means to diagnose
the high-line/premium CTM, the CCD data bus net-
work, and the electronic modules that provide inputs
to or receive outputs from the high-line/premium
CTM requires the use of a DRBIIItscan tool and the
appropriate diagnostic information. The DRBIIIt
scan tool can provide confirmation that the CCD data
bus network is functional, that all of the electronic
modules are sending and receiving the proper mes-
sages over the CCD data bus, and that the CTM is
receiving the proper hard wired inputs and respond-ing with the proper hard wired outputs needed to
perform its many functions.
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: The following tests may not prove conclu-
sive in the diagnosis of the high-line or premium
versions of the Central Timer Module (CTM). The
most reliable, efficient, and accurate means to diag-
nose the high-line or premium CTM requires the
use of a DRBIIITscan tool and the appropriate diag-
nostic information.
(1) Check the fused B(+) fuse (Fuse 13 - 10
ampere) in the Junction Block (JB). If OK, go to Step
2. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
(Fuse 13 - 10 ampere) in the JB. If OK, go to Step 3.
If not OK, repair the open fused B(+) circuit between
the JB and the Power Distribution Center (PDC) as
required.
(3) For a base version CTM, check the fused igni-
tion switch output (st-run) fuse (Fuse 11 - 10 ampere)
in the JB. For a high-line/premium version CTM,
check the fused ignition switch output (run-acc) fuse
(Fuse6-25ampere) in the JB. 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. 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
8E - 4 ELECTRONIC CONTROL MODULESBR/BE
BODY CONTROL/CENTRAL TIMER MODULE (Continued)

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/premiumCTM 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).
(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.
Fig. 3 Central Timer Module (Base) Remove/Install
1 - SCREWS
2 - BRACKET
3 - WIRE HARNESS CONNECTOR
4 - CENTRAL TIMER MODULE (BASE)
BR/BEELECTRONIC CONTROL MODULES 8E - 5
BODY CONTROL/CENTRAL TIMER MODULE (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.
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) 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 C2D ) data bus system is a multiplex sys-
tem used for vehicle communications on many
Chrysler Corporation vehicles. Within the context 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 Chrysler vehicles use this principle for
communication between the various microprocessor-
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 (HIGH-LINE/PREMIUM)
8E - 6 ELECTRONIC CONTROL MODULESBR/BE
BODY CONTROL/CENTRAL TIMER MODULE (Continued)

A vehicle that has not been operated for approxi-
mately twenty days, may discharge the battery to an
inadequate level. When a vehicle will not be used for
twenty days or more (stored), remove the IOD fuse
from the Power Distribution Center (PDC). This will
reduce battery discharging.
Excessive IOD can be caused by:
²Electrical items left on.
²Faulty or improperly adjusted switches.
²Faulty or shorted electronic modules and compo-
nents.
²An internally shorted generator.
²Intermittent shorts in the wiring.If the IOD is over thirty-five milliamperes, the
problem must be found and corrected before replac-
ing a battery. In most cases, the battery can be
charged and returned to service after the excessive
IOD condition has been corrected.
(1) Verify that all electrical accessories are off.
Turn off all lamps, remove the ignition key, and close
all doors. If the vehicle is equipped with an illumi-
nated entry system or an electronically tuned radio,
allow the electronic timer function of these systems
to automatically shut off (time out). This may take
up to three minutes. See the Electronic Module Igni-
tion-Off Draw Table for more information.
ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
ModuleTime Out?
(If Yes, Interval And Wake-Up Input)IODIOD After Time
Out
Radio No1to3
milliamperesN/A
Audio Power
AmplifierNoup to 1
milliampereN/A
Central Timer Module
(CTM)No4.75
milliamperes
(max.)N/A
Powertrain Control
Module (PCM)No 0.95 milliampere N/A
ElectroMechanical
Instrument Cluster
(EMIC)No 0.44 milliampere N/A
Combination Flasher No 0.08 milliampere N/A
(2) Determine that the underhood lamp is operat-
ing properly, then disconnect the lamp wire harness
connector or remove the lamp bulb.
(3) Disconnect the battery negative cable.
(4) Set an electronic digital multi-meter to its
highest amperage scale. Connect the multi-meter
between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up to
three minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.(5) After about three minutes, the high-amperage
IOD reading on the multi-meter should become very
low or nonexistent, depending upon the electrical
equipment in the vehicle. If the amperage reading
remains high, remove and replace each fuse or circuit
breaker in the Power Distribution Center (PDC) and
then in the Junction Block (JB), one at a time until
the amperage reading becomes very low, or nonexist-
ent. Refer to the appropriate wiring information in
this service manual for complete PDC and JB fuse,
circuit breaker, and circuit identification. This will
isolate each circuit and identify the circuit that is the
source of the high-amperage IOD. If the amperage
reading remains high after removing and replacing
each fuse and circuit breaker, disconnect the wire
harness from the generator. If the amperage reading
now becomes very low or nonexistent, refer to Charg-
ing System for the proper charging system diagnosis
and testing procedures. After the high-amperage IOD
has been corrected, switch the multi-meter to pro-
gressively lower amperage scales and, if necessary,
repeat the fuse and circuit breaker remove-and-re-
8F - 16 BATTERY SYSTEMBR/BE
BATTERY (Continued)

ifications have common physical dimensions, current
capacities, terminal patterns, and terminal functions.
The ISO micro-relay terminal functions are the same
as a conventional ISO relay. However, the ISO micro-
relay terminal pattern (or footprint) is different, the
current capacity is lower, and the physical dimen-
sions are smaller than those of the conventional ISO
relay.
The heated seat relay cannot be repaired or
adjusted and, if faulty or damaged, it must be
replaced.
OPERATION
The ISO relay consists of an electromagnetic coil, a
resistor or diode, and three (two fixed and one mov-
able) electrical contacts. The movable (common feed)
relay contact is held against one of the fixed contacts
(normally closed) by spring pressure. When the elec-
tromagnetic coil is energized, it draws the movable
contact away from the normally closed fixed contact,
and holds it against the other (normally open) fixed
contact. When the electromagnetic coil is de-ener-
gized, spring pressure returns the movable contact to
the normally closed position. The resistor or diode is
connected in parallel with the electromagnetic coil in
the relay, and helps to dissipate voltage spikes that
are produced when the coil is de-energized.
The heated seat relay is controlled by the premium
version of the Central Timer Module (CTM), which
controls the ground feed to the coil ground terminal
of the relay to energize and de-energize the electro-
magnetic coil of the relay. The CTM monitors engine
operation through messages it receives from the Pow-
ertrain Control Module (PCM) over the Chrysler Col-
lision Detection (CCD) data bus network. The CTM is
programmed to energize the relay only when the
engine is running, and to de-energize the relay when
the engine is not running. Refer toCentral Timer
Modulein the index of this service manual for the
location of more information on the premium CTM.
DIAGNOSIS & TESTING - HEATED SEAT RELAY
The heated seat relay (Fig. 7) is located in the
Junction Block (JB) on the left end of the instrument
panel in the passenger compartment of the vehicle.
Refer toWiring Diagramsfor the location of com-
plete heated seat system wiring diagrams.
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.
RELAY TEST
(1) Remove the heated seat relay from the JB.
Refer toHeated Seat Relayin this section for the
location of the proper heated seat relay removal pro-
cedures.
(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, perform the Relay Circuit Test that
follows. If not OK, replace the faulty relay.
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the fused B(+) fuse in the Power Distribu-
tion Center (PDC) as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
Fig. 7 Heated Seat Relay
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
8G - 12 HEATED SEAT SYSTEMBR/BE
HEATED SEAT RELAY (Continued)

(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the heated seat module. There should be continu-
ity between the cavity for relay terminal 87 and the
B(+) to heated seat module circuit cavity of the
heated seat module wire harness connector at all
times. If OK, go to Step 4. If not OK, repair the open
B(+) to heated seat module circuit to the heated seat
module as required.
(4) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is connected to bat-
tery voltage and should be hot at all times. Check for
battery voltage at the cavity for relay terminal 86. If
OK, go to Step 5. If not OK, repair the open circuit to
the fused B(+) fuse in the PDC as required.
(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded by the
premium version of the Central Timer Module (CTM)
in response to an engine speed message received over
the Chrysler Collision Detection (CCD) data bus from
the Powertrain Control Module (PCM) when the
engine is running. Check for continuity between the
cavity for relay terminal 85 and the heated seat relay
control circuit cavity of the CTM wire harness con-
nector. There should be continuity at all times. If OK,
use a DRBIIItscan tool and the proper diagnostic
procedures manual to test the operation of the CTM
and CCD data bus. If not OK, repair the open heated
seat relay control circuit as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the fuse access panel by inserting a
finger in the finger recess molded into the panel and
then pulling the panel sharply away from the left
outboard end of the instrument panel.
(3) The heated seat relay is located on the forward
side of the Junction Block (JB), just above the com-
bination flasher (Fig. 8).
(4) Grasp the heated seat relay firmly and pull it
straight out from the JB.
INSTALLATION
(1) Position the heated seat relay in the proper
receptacle in the JB.
(2) Align the heated seat relay terminals with the
terminal cavities in the JB receptacle.
(3) Push in firmly on the heated seat relay until
the terminals are fully seated in the terminal cavities
in the JB receptacle.
(4) Insert the tabs on the forward edge of the fuse
access panel in the notches on the forward edge of
the instrument panel fuse access panel opening.(5) Press the rear edge of the fuse access panel in
toward the instrument panel until the panel snaps
back into place.
(6) Reconnect the battery negative cable.
PASSENGER SEAT HEATER
SWITCH
DESCRIPTION
The heated seat switches used on vehicles with
this option are both mounted in a heated seat switch
bezel (Fig. 9), which replaces the standard equipment
cubby bin located in the lower right corner of the
instrument cluster bezel next to the radio receiver.
The two switches are snapped into the mounting
holes of the heated seat switch bezel, and the heated
seat switch bezel is secured with three screws to the
instrument panel. The mounts for the heated seat
switch bezel are concealed behind the instrument
cluster bezel. The two heated seat switches are iden-
tical in appearance and construction, except for the
location of a keyway in the single connector recepta-
cle on the back of each switch. The instrument panel
wire harness connectors for the heated seat switches
are keyed to match the connector receptacles on the
switches so that the two heated seat switches can
only be connected to the proper heated seat.
Fig. 8 Heated Seat
1 - JUNCTION BLOCK
2 - HEATED SEAT RELAY
3 - INSTRUMENT PANEL
4 - COMBINATION FLASHER
BR/BEHEATED SEAT SYSTEM 8G - 13
HEATED SEAT RELAY (Continued)