1998 DODGE RAM 1500 Turn signal switch

²Data link connection for DRB scan tool
²EATX module (if equipped)
²Engine coolant temperature sensor
²Fuel level (through J1850 circuitry)
²Generator (battery voltage) output
²Ignition circuit sense (ignition switch in on/off/
crank/run position)
²Intake manifold air temperature sensor
²Knock sensors (2 on 3.7L engine)
²Leak detection pump (switch) sense (if equipped)
²Manifold absolute pressure (MAP) sensor
²Oil pressure
²Oxygen sensors
²Park/neutral switch (auto. trans. only)
²Power ground
²Power steering pressure switch (if equipped)
²Sensor return
²Signal ground
²Speed control multiplexed single wire input
²Throttle position sensor
²Transfer case switch (4WD range position)
²Vehicle speed signal
NOTE: PCM Outputs:
²A/C clutch relay
²Auto shutdown (ASD) relay
²J1850 bus (+/-) circuits for: speedometer, voltme-
ter, fuel gauge, oil pressure gauge/lamp, engine temp.
gauge and speed control warn. lamp
²Data link connection for DRB scan tool
²EGR valve control solenoid (if equipped)
²EVAP canister purge solenoid
²Five volt sensor supply (primary)
²Five volt sensor supply (secondary)
²Fuel injectors
²Fuel pump relay
²Generator field driver (-)
²Generator field driver (+)
²Idle air control (IAC) motor
²Ignition coil(s)
²Leak detection pump (if equipped)
²Malfunction indicator lamp (Check engine lamp).
Driven through J1850 circuits.²Oxygen sensor heater relays
²Oxygen sensors (pulse width modulated)
²Radiator cooling fan relay (pulse width modu-
lated)
²Speed control vacuum solenoid
²Speed control vent solenoid
²Tachometer (if equipped). Driven through J1850
circuits.
²Transmission convertor clutch circuit. Driven
through J1850 circuits.
OPERATION - 5 VOLT SUPPLIES
Primary 5±volt supply:
²supplies the required 5 volt power source to the
Crankshaft Position (CKP) sensor.
²supplies the required 5 volt power source to the
Camshaft Position (CMP) sensor.
²supplies a reference voltage for the Manifold
Absolute Pressure (MAP) sensor.
²supplies a reference voltage for the Throttle
Position Sensor (TPS) sensor.
Secondary 5±volt supply:
²supplies the required 5 volt power source to the
oil pressure sensor.
²supplies the required 5 volt power source for the
Vehicle Speed Sensor (VSS) (if equipped).
²supplies the 5 volt power source to the transmis-
sion pressure sensor (certain automatic transmis-
sions).
OPERATION - IGNITION CIRCUIT SENSE
The ignition circuit sense input tells the PCM the
ignition switch has energized the ignition circuit.
Battery voltage is also supplied to the PCM
through the ignition switch when the ignition is in
the RUN or START position. This is referred to as
the9ignition sense9circuit and is used to9wake up9
the PCM. Voltage on the ignition input can be as low
as 6 volts and the PCM will still function. Voltage is
supplied to this circuit to power the PCM's 8-volt reg-
ulator and to allow the PCM to perform fuel, ignition
and emissions control functions.
DRELECTRONIC CONTROL MODULES 8E - 11
POWERTRAIN CONTROL MODULE (Continued)

(8) If the previous step is not performed, a Diag-
nostic Trouble Code (DTC) will be set.
(9) If necessary, use DRB IIItScan Tool to erase
any Diagnostic Trouble Codes (DTC's) from PCM.
Also use the DRB scan tool to reprogram new PCM
with vehicles original Vehicle Identification Number
(VIN) and original vehicle mileage.
SENTRY KEY IMMOBILIZER
MODULE
DESCRIPTION
The Sentry Key Immobilizer Module (SKIM) con-
tains a Radio Frequency (RF) transceiver and a cen-
tral processing unit, which includes the Sentry Key
Immobilizer System (SKIS) program logic. The SKIS
programming enables the SKIM to program and
retain in memory the codes of at least two, but no
more than eight electronically coded Sentry Key
transponders. The SKIS programming also enables
the SKIM to communicate over the Programmable
Communication Interface (PCI) bus network with the
Powertrain Control Module (PCM) or Electronic Con-
trol Module (ECM), depending on engine application,
and/or the DRBIIItscan tool.
OPERATION
The SKIM transmits and receives RF signals
through a tuned antenna enclosed within a molded
plastic ring that is integral to the SKIM housing.
When the SKIM is properly installed on the steering
column, the antenna ring is oriented around the igni-
tion lock cylinder housing. This antenna ring must be
located within eight millimeters (0.31 inches) of the
Sentry Key in order to ensure proper RF communica-
tion between the SKIM and the Sentry Key tran-
sponder.
For added system security, each SKIM is pro-
grammed with a unique ªSecret Keyº code and a
security code. The SKIM keeps the ªSecret Keyº code
in memory. The SKIM also sends the ªSecret Keyº
code to each of the programmed Sentry Key tran-
sponders. The security code is used by the assembly
plant to access the SKIS for initialization, or by the
dealer technician to access the system for service.
The SKIM also stores in its memory the Vehicle
Identification Number (VIN), which it learns through
a PCI bus message from the PCM (NGC) or ECM
(Cummins) during initialization.The SKIM and the PCM/ECM both use software
that includes a rolling code algorithm strategy, which
helps to reduce the possibility of unauthorized SKIS
disarming. The rolling code algorithm ensures secu-
rity by preventing an override of the SKIS through
the unauthorized substitution of the SKIM or the
PCM/ECM. However, the use of this strategy also
means that replacement of either the SKIM or the
PCM/ECM units will require a system initialization
procedure to restore system operation.
When the ignition switch is turned to the ON or
START positions, the SKIM transmits an RF signal
to excite the Sentry Key transponder. The SKIM then
listens for a return RF signal from the transponder
of the Sentry Key that is inserted in the ignition lock
cylinder. If the SKIM receives an RF signal with
valid ªSecret Keyº and transponder identification
codes, the SKIM sends a ªvalid keyº message to the
PCM/ECM over the PCI bus. If the SKIM receives an
invalid RF signal or no response, it sends ªinvalid
keyº messages to the PCM/ECM. The PCM/ECM will
enable or disable engine operation based upon the
status of the SKIM messages.
The SKIM also sends messages to the Instrument
Cluster which controls the VTSS indicator LED. The
SKIM sends messages to the Instrument Cluster to
turn the LED on for about three seconds when the
ignition switch is turned to the ON position as a bulb
test. After completion of the bulb test, the SKIM
sends bus messages to keep the LED off for a dura-
tion of about one second. Then the SKIM sends mes-
sages to turn the LED on or off based upon the
results of the SKIS self-tests. If the VTSS indicator
LED comes on and stays on after the bulb test, it
indicates that the SKIM has detected a system mal-
function and/or that the SKIS has become inopera-
tive.
If the SKIM detects an invalid key when the igni-
tion switch is turned to the ON position, it sends
messages to flash the VTSS indicator LED. The
SKIM can also send messages to flash the LED as an
indication to the customer that the SKIS has been
placed in it's ªCustomer Learnº programming mode.
See Sentry Key Immobilizer System Transponder
Programming in this section for more information on
the ªCustomer Learnº programming mode.
For diagnosis or initialization of the SKIM and the
PCM/ECM, a DRBIIItscan tool and the proper Pow-
ertrain Diagnostic Procedures manual are required.
The SKIM cannot be repaired and, if faulty or dam-
aged, the unit must be replaced.
DRELECTRONIC CONTROL MODULES 8E - 13
POWERTRAIN CONTROL MODULE (Continued)

TRANSFER CASE CONTROL
MODULE
DESCRIPTION
The Transfer Case Control Module (TCCM) (Fig. 8)
is a microprocessor-based assembly, controlling the
4X4 transfer case shift functions via the actuation of
a shift motor and utilizing the feedback of a mode
sensor assembly. Communication is via the PCI serial
bus. Inputs include user selectable 4X4 modes that
include 2WD, AWD, 4HI, 4LO, and Neutral. The logic
and driver circuitry is contained in a molded plastic
housing with an embedded heat-sink and is located
behind the left side of the lower instrument panel.
OPERATION
The Transfer Case Control Module (TCCM) utilizes
the input from the transfer case mounted mode sen-
sor, the instrument panel mounted selector switch,
and the following information from the vehicle's PCI
serial bus to determine if a shift is allowed.
²Engine RPM and Vehicle Speed
²Diagnostic Requests
²Manual Transmission and Brake Applied
²PRNDL
²Ignition Status
²ABS Messages
Once the TCCM determines that a requested shift
is allowed, it actuates the bi-directional shift motor
as necessary to achieve the desired transfer case
operating mode. The TCCM also monitors the mode
sensor while controlling the shift motor to determine
the status of the shift attempt.Several items can cause the requested shift not to
be completed. If the TCCM has recognized a fault
(DTC) of some variety, it will begin operation in one
of four Functionality Levels. These levels are:
²Level Zero- Normal Operation.
²Level One- Only Mode Shifts Are Allowed.
²Level Two- Only Mode Shifts and Shifts Into
LOW Are Allowed (No Neutral Shifts Are Allowed).
²Level Three- No Shifts Are Allowed
The TCCM can also be operating in one of three
possible power modes. These power modes are:
²Full Power Modeis the normal operational
mode of the module. This mode is achieved by normal
PCI bus traffic being present and the ignition being
in the RUN position.
²Reduced Power Modewill be entered when
the ignition has been powered off. In this state, the
module will shut down power supplied to external
devices, and to electronic interface inputs and out-
puts. From this state the module can enter either
Sleep Mode or Full Power Mode. To enter this mode,
the module must receive an ignition message denot-
ing that the ignition is off, or not receive any mes-
sages for 5  0.5 seconds. To exit this mode, the
module must receive one ignition message that
denotes that the ignition is in the RUN position.
²Sleep Modewill be entered, from the Reduced
Power Mode, when no PCI traffic has been sensed for
20  1 seconds. If during Sleep Mode the module
detects PCI bus traffic, it will revert to the Reduced
Power mode while monitoring for ignition messages.
It will remain in this state as long as there is traffic
other than run or start messages, and will return to
Sleep mode if the bus goes without traffic for 20  1
seconds.
SHIFT REQUIREMENTS
If the TCCM is in full power mode and at function-
ality level zero, it uses the following criteria to deter-
mine if a shift is allowed.
If any of the driver controllable conditions are not
met once the shift request is recognized, the TCCM
will solidly illuminate the source position's LED and
flash the desired position's LED for all shifts except
NEUTRAL. The NEUTRAL shift LED strategy will
be discussed later.
Mode shiftswill be allowed regardless of trans-
mission gear or vehicle speed, whenever the following
conditions are met:
²Front and rear wheel speed are within 21 km/hr
(13 mph).
²A change in the Selector switch state indicates
that a mode shift has been requested.
²A valid mode sensor signal is being sensed by
the TCCM.
Fig. 8 Transfer Case Control Module (TCCM)
Location
1 - INSTRUMENT PANEL
2 - TRANSFER CASE CONTROL MODULE (TCCM)
3 - TRANSFER CASE SELECTOR SWITCH
8E - 16 ELECTRONIC CONTROL MODULESDR

(5) Install the appropriate seat cushion or seat
back trim cover. Make certain the seat wire harness
is correctly routed through the seat and seat back.
HEATED SEAT SENSOR
DESCRIPTION
The heated seat temperature sensor is a Negative
Temperature Coefficient (NTC) thermistor. One tem-
perature sensor is used for each seat. This tempera-
ture sensor is located in the seat cushion heating
element on all models.
The heated seat temperature sensor cannot be
repaired or adjusted and must be replaced if defec-
tive. The heated seat cushion element must be
replaced if the temperature sensor is defective. Refer
to the procedure in this section of the service man-
ual.
OPERATION
When the temperature of the seat cushion cover
rises, the resistance of the sensor decreases. The
heated seat module supplies five-volts to one side of
each sensor, and monitors the voltage drop through
the sensor on a return circuit. The heated seat mod-
ule uses this temperature sensor input to monitor
the temperature of the seat, and regulates the cur-
rent flow to the seat heating elements accordingly.
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR
NOTE: Any resistance values (OHMSV) given in the
following text are supplied using the automatic
range generated by a FLUKETautomotive meter. If
another type of measuring device is used, the val-
ues generated may not be the same as the results
shown here, or may have to be converted to the
range used here.
(1) Position the driver seat in the full rearward
position.
(2) Unclip the heated seat module from the bottom
of the drivers seat cushion pan.
(3) Back-probe the heated seat module wire har-
ness connector, do not disconnect. Check cavity (#7
for passenger, #8 for driver seat) for a range in volt-
age from approx. 1.72 ± 3.0 volts. It should be within
this range, If OK check the heated seat element. If
NOT OK, check for the proper 5 volt supply to the
heated seat sensor, from the module. Refer to Wiring
for specific information. If 5 volts is not being sup-
plied to the sensor from the module, replace the
heated seat module.
(4) Test the seat wire harness between the heated
seat module connector and the heated seat wire har-
ness connector for shorted or open circuits. If OK,
refer toDiagnosis and Testing the Heated Seat
Modulein Electronic Control Modules, for the
proper heated seat module diagnosis and testing pro-
cedures. If not OK, repair the shorted or open heated
seat wire harness as required.
REMOVAL
(1) For heated seat sensor replacement procedure
(Refer to 8 - ELECTRICAL/HEATED SEATS/
HEATED SEAT ELEMENT - REMOVAL).
HEATED SEAT SWITCH
DESCRIPTION
The momentary, bidirectional rocker-type heated
seat switch (Fig. 4) provides a resistor-multiplexed
signal to the heated seat module via a mux circuit.
Each switch has a center neutral position and
momentary Low and High positions so that both the
driver and the front seat passenger can select a pre-
ferred level of seat heating. Each heated seat switch
has two Light-Emitting Diode (LED) indicator lamps,
which indicate the selected mode (Low or High) of
the seat heater. These indicator lamps also provide
diagnostic feedback for the heated seat system. Each
switch also has an incandescent bulb, which provides
Fig. 3 Heating Element Installation
1 - ORIGINAL (INOPERATIVE) HEATING ELEMENT
2 - REPLACEMENT HEATING ELEMENT
DRHEATED SEAT SYSTEM 8G - 11
HEATED SEAT ELEMENT (Continued)

dimmer controlled back lighting of the switch when
the headlamps or park lamps are on.
The heated seat switches are both mounted in the
instrument panel center bezel, located in the lower
center of the instrument panel. The two switches are
snapped into the mounting holes of the heated seat
switch bezel, and the heated seat switch bezel is
secured with screws to the instrument panel center
bezel. The heated seat switches are differentiated by
the keyway in the connector receptacle on the backs
of the switches and keyway on the switch housing.
The instrument panel wire harness connectors for
the heated seat switches are keyed to match the con-
nector receptacles on the switches so that the two
heated seat switches can only be connected to the
proper heated seat electrical.
The two LED indicator lamps and the incandescent
bulb in each heated seat switch cannot be repaired. If
the indicator lamps or back lighting bulb are faulty
or damaged, the individual heated seat switch must
be replaced.
OPERATION
The heated seat switches receive battery current
through a fused ignition switch output (run) circuit
when the ignition switch is in the On position.
Depressing the heated seat switch rocker to its
momentary High or Low position provides a hard-
wired resistance signal to the heated seat module.
This signal tells the module to energize the heatedseat element of the selected seat and maintain the
requested temperature setting. If the heated seat
switch is depressed to a different position (Low or
High) than the currently selected state, the heated
seat module will change states to support the new
selection. If a heated seat switch is depressed a sec-
ond time, the heated seat module interprets the sec-
ond input as a request to turn the seat heater OFF.
The High and Low LED indicator lamps in the
heated seat switches receive battery current through
a fused ignition switch output (run) circuit when the
ignition switch is in the On position. The ground side
of each indicator lamp is controlled by the heated
seat module. This control of the switch indicator
lamps also allows the module to provide diagnostic
feedback to the vehicle operator or technician to indi-
cate heated seat system faults by flashing the indica-
tor lamps on and off. One side of the incandescent
back lighting bulb in each heated seat switch is con-
nected to ground at all times. The other side of the
incandescent bulb is connected to the fused panel
lamps dimmer switch signal circuit. These bulbs are
energized when the park lamps or headlamps are
turned on, and their illumination intensity is con-
trolled by the panel lamps dimmer switch.
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH
Refer toWiring Diagramsfor connector pin-outs
and the location of complete heated seat system wir-
ing diagrams.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
(1) If the problem being diagnosed involves inoper-
ative heated seat switch back lighting and the cluster
illumination lamps operate, go to Step 2. If the prob-
lem being diagnosed involves inoperative heated seat
switch back lighting and the cluster illumination
lamps are also inoperative, (Refer to 8 - ELECTRI-
CAL/INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). If the problem being diagnosed involves
inoperative heated seat switch indicator lamps and
the heated seat elements do not heat, proceed. If the
Fig. 4 HEATED SEAT SWITCH
1 - HEATED SEAT SWITCH
2 - LIGHT-EMITTING DIODE (LED) INDICATOR LAMPS
8G - 12 HEATED SEAT SYSTEMDR
HEATED SEAT SWITCH (Continued)

problem being diagnosed involves inoperative heated
seat switch indicator lamps and the heated seat ele-
ments do heat, go to Step 6. If the problem being
diagnosed involves a heated seat switch indicator
lamp that remains illuminated after the heated seat
has been turned Off, (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/MEMORY
HEATED SEAT/MIRROR MODULE - DIAGNOSIS
AND TESTING).
(2) Disconnect and isolate the battery negative
cable. Remove the heated seat switch and bezel unit
from the instrument panel. Disconnect the heated
seat switch to be tested. Check for continuity
between the ground circuit cavity of the heated seat
switch and a good ground. There should be continu-
ity. If OK, go to Step 3. If not OK, repair the open
ground circuit to ground as required.
(3) Reconnect the battery negative cable. Turn the
park lamps on with the headlamp switch. Rotate the
panel lamps dimmer thumb wheel on the headlamp
switch upward to just before the interior lamps
detent. Check for battery voltage at the fused panel
lamps dimmer circuit cavity of the heated seat
switch. If OK, go to Step 4. If not OK, repair the
open fused panel lamps dimmer switch signal circuit
to the fuse in the Integrated Power Module as
required.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run) circuit cavity of the heated seat switch.
If OK, go to Step 5. If not OK, repair the open fused
ignition switch output (run) circuit as required.
(5) Check the continuity and resistance values of
the heated seat switch in the Neutral, Low and High
positions as shown in the Heated Seat Switch Conti-
nuity chart. If OK, refer to Step 6. If not OK, replace
the faulty heated seat switch.
HEATED SEAT SWITCH CONTINUITY
Switch PositionContinuity
BetweenResistance
Neutral 4 & 6 2.2 Kilohms
Low 4 & 6 .415 Kilohms
High 4 & 6 33 Ohms
(6) Replace the inoperative heated seat switch
with a known good unit and test the operation of the
switch indicator lamps. If OK, discard the faulty
heated seat switch. If not OK, (Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/
MEMORY HEATED SEAT/MIRROR MODULE -
DIAGNOSIS AND TESTING).
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Wait two minutes for the system reserve capac-
itor to discharge before beginning any airbag or
instrument panel service.
(3) Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL).
(4) Remove the screws that secure the heated seat
switch bezel to the instrument panel center bezel.
(5) Remove the heated seat switch bezel and both
switches from the instrument panel as a unit.
(6) From the back of the heated seat switch bezel,
gently pry the switch free and push the heated seat
switch out through the front of the bezel.
INSTALLATION
NOTE: When installing the heated seat switches, be
certain they are installed in the proper mounting
holes of the heated seat switch bezel. The heated
seat switches are differentiated by the keyway in
the connector receptacle on the backs of the
switches and keyway on the switch housing (Fig.
4).
(1) From the back of the heated seat switch bezel,
gently push the heated seat switch in through the
front of the bezel.
(2) Position the heated seat switch bezel to the
instrument panel center bezel and install the retain-
ing screws.
(3) Install the center bezel on the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(4) Connect the battery negative cable.
(5) Verify vehicle and system operation.
HEATED SEAT MODULE
DESCRIPTION
The heated seat module is also known as the Seat
Heat Interface Module. The heated seat module (Fig.
5) is located under the drivers front seat cushion,
where it is secured to a mounting bracket. The
heated seat module has a single connector receptacle
that allows the module to be connected to all of the
required inputs and outputs through the seat wire
harness.
DRHEATED SEAT SYSTEM 8G - 13
HEATED SEAT SWITCH (Continued)

Sandwiched between the rear cover and the lens,
hood and mask unit is the cluster housing. The
molded plastic cluster housing serves as the carrier
for the cluster circuit board and circuitry, the cluster
connector receptacles, the RKE interface connector,
the gauges, a Light Emitting Diode (LED) for each
cluster indicator, two VFD units, an audible tone
generator, the cluster overlay, the gauge pointers, the
odometer/trip odometer switch and the switch button.
The cluster overlay is a laminated plastic unit. The
dark, visible, outer surface of the overlay is marked
with all of the gauge dial faces and graduations, but
this layer is also translucent. The darkness of this
outer layer prevents the cluster from appearing clut-
tered or busy by concealing the cluster indicators
that are not illuminated, while the translucence of
this layer allows those indicators and icons that are
illuminated to be readily visible. The underlying
layer of the overlay is opaque and allows light from
the LED for each of the various indicators and the
incandescent illumination lamps behind it to be visi-
ble through the outer layer of the overlay only
through predetermined stencil-like cutouts. A rectan-
gular opening in the overlay at the base of both the
speedometer and tachometer dial faces has a smoked
clear lens through which the illuminated VFD units
can be viewed.
Several versions of the EMIC module are offered
on this model. These versions accommodate all of the
variations of optional equipment and regulatory
requirements for the various markets in which the
vehicle will be offered. The microprocessor-based
EMIC utilizes integrated circuitry and information
carried on the Programmable Communications Inter-
face (PCI) data bus network along with several hard
wired analog and multiplexed inputs to monitor sen-
sors and switches throughout the vehicle. In response
to those inputs, the internal circuitry and program-
ming of the EMIC allow it to control and integrate
many electronic functions and features of the vehicle
through both hard wired outputs and the transmis-
sion of electronic message outputs to other electronic
modules in the vehicle over the PCI data bus. (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/COMMUNICATION - DESCRIPTION -
PCI BUS).
Besides typical instrument cluster gauge and indi-
cator support, the electronic functions and features
that the EMIC supports or controls include the fol-
lowing:
²Audible Warnings- The EMIC electronic cir-
cuit board is equipped with an audible tone generator
and programming that allows it to provide various
audible alerts to the vehicle operator, including
chime tones and beep tones. An electromechanical
relay is also soldered onto the circuit board to pro-duce audible clicks that emulate the sound of a con-
ventional turn signal or hazard warning flasher.
(Refer to 8 - ELECTRICAL/CHIME/BUZZER -
DESCRIPTION).
²Brake Lamp Control- The EMIC provides
electronic brake lamp request messages to the Front
Control Module (FCM) located on the Integrated
Power Module (IPM) for brake lamp control, exclud-
ing control of the Center High Mounted Stop Lamp
(CHMSL), which remains controlled by a direct hard
wired output of the brake lamp switch.
²Brake Transmission Shift Interlock Control
- The EMIC monitors inputs from the brake lamp
switch, ignition switch, and the Transmission Range
Sensor (TRS), then controls a high-side driver output
to operate the Brake Transmission Shift Interlock
(BTSI) solenoid that locks and unlocks the automatic
transmission gearshift selector lever on the steering
column.
²Cargo Lamp Control- The EMIC provides
direct control of cargo lamp operation with a load
shedding (battery saver) feature which will automat-
ically turn off the cargo lamp if it remains on after a
timed interval.
²Central Locking- The EMIC provides support
for the central locking feature of the power lock sys-
tem. This feature will lock or unlock all doors based
upon the input from the door cylinder lock switch.
Door cylinder lock switches are used only on models
equipped with the optional Vehicle Theft Security
System (VTSS).
²Door Lock Inhibit- The EMIC inhibits locking
of the doors with the power lock switch when the key
is in the ignition switch and the driver side front
door is ajar. However, operation of the door locks is
not inhibited under the same conditions when the
Lock button of the optional RKE transmitter is
depressed.
²Enhanced Accident Response- The EMIC
monitors an input from the Airbag Control Module
(ACM) and, following an airbag deployment, will
immediately disable the power lock output, unlock all
doors by activating the power unlock output, then
enables the power lock output. This feature, like all
other enhanced accident response features, is depen-
dent upon a functional vehicle electrical system fol-
lowing the vehicle impact event.
²Exterior Lighting Control- The EMIC pro-
vides electronic head lamp and/or park lamp request
messages to the Front Control Module (FCM) located
on the Integrated Power Module (IPM) for the appro-
priate exterior lamp control of standard head and
park lamps, as well as optional front fog lamps. This
includes support for headlamp beam selection and
the optical horn feature, also known as flash-to-pass.
DRINSTRUMENT CLUSTER 8J - 3
INSTRUMENT CLUSTER (Continued)

²Exterior Lighting Fail-safe- In the absence of
a headlamp switch input, the EMIC will turn on the
cluster illumination lamps and provide electronic
headlamp low beam and park lamp request messages
to the Front Control Module (FCM) located on the
Integrated Power Module (IPM) for default exterior
lamp operation. The FCM will also provide default
park lamp and headlamp low beam operation and the
EMIC will turn on the cluster illumination lamps if
there is a failure of the electronic data bus commu-
nication between the EMIC and the FCM.
²Heated Seat Control- The EMIC monitors
inputs from the ignition switch and electronic engine
speed messages from the Powertrain Control Module
(PCM) to control a high side driver output to the
heated seat switch Light Emitting Diode (LED) indi-
cators. This input allows the heated seat switches to
wake up the heated seat module if the switch is actu-
ated. The EMIC will de-energize the heated seat
switch LED indicators, which deactivates the heated
seat system, if the ignition switch is turned to any
position except On or Start, or if the engine speed
message indicates zero. (Refer to 8 - ELECTRICAL/
HEATED SEATS - DESCRIPTION).
²Interior Lamp Load Shedding- The EMIC
provides a battery saver feature which will automat-
ically turn off all interior lamps that remain on after
a timed interval of about fifteen minutes.
²Interior Lamps - Enhanced Accident
Response- The EMIC monitors inputs from the Air-
bag Control Module (ACM) and the Powertrain Con-
trol Module (PCM) to automatically turn on the
interior lighting after an airbag deployment event
ten seconds after the vehicle speed is zero. The inte-
rior lighting remains illuminated until the key is
removed from the ignition switch lock cylinder, at
which time the interior lighting returns to normal
operation and control. This feature, like all other
enhanced accident response features, is dependent
upon a functional vehicle electrical system following
the vehicle impact event.
²Interior Lighting Control- The EMIC moni-
tors inputs from the interior lighting switch, the door
ajar switches, the cargo lamp switch, the reading
lamp switches, and the Remote Keyless Entry (RKE)
module to provide courtesy lamp control. This
includes support for timed illuminated entry with
theater-style fade-to-off and courtesy illumination
defeat features.
²Lamp Out Indicator Control- The EMIC
monitors electronic lamp outage messages from the
Front Control Module (FCM) located on the Inte-
grated Power Module (IPM) in order to provide lamp
out indicator control for the headlamps (low and high
beams), turn signal lamps, and the brake lamps
(excluding CHMSL).²Panel Lamps Dimming Control- The EMIC
provides a hard wired 12-volt Pulse-Width Modulated
(PWM) output that synchronizes the dimming level
of all hard wired panel lamps dimmer controlled
lamps with that of the cluster illumination lamps.
²Parade Mode- The EMIC provides a parade
mode (also known as funeral mode) that allows all
Vacuum-Fluorescent Display (VFD) units in the vehi-
cle to be illuminated at full (daytime) intensity while
driving during daylight hours with the exterior
lamps turned on.
²Power Locks- The EMIC monitors inputs from
the power lock switches and the Remote Keyless
Entry (RKE) receiver module (optional) to provide
control of the power lock motors through high side
driver outputs to the power lock motors. This
includes support for rolling door locks (also known as
automatic door locks), automatic door unlock, a door
lock inhibit mode, and central locking (with the
optional Vehicle Theft Security System only). (Refer
to 8 - ELECTRICAL/POWER LOCKS - DESCRIP-
TION).
²Remote Keyless Entry- The EMIC supports
the optional Remote Keyless Entry (RKE) system fea-
tures, including support for the RKE Lock, Unlock
(with optional driver-door-only unlock, and unlock-
all-doors), Panic, audible chirp, optical chirp, illumi-
nated entry modes, an RKE programming mode, as
well as optional Vehicle Theft Security System
(VTSS) arming (when the proper VTSS arming con-
ditions are met) and disarming.
²Remote Radio Switch Interface- The EMIC
monitors inputs from the optional remote radio
switches and then provides the appropriate electronic
data bus messages to the radio to select the radio
operating mode, volume control, preset station scan
and station seek features.
²Rolling Door Locks- The EMIC provides sup-
port for the power lock system rolling door locks fea-
ture (also known as automatic door locks). This
feature will automatically lock all unlocked doors
each time the vehicle speed reaches twenty-four kilo-
meters-per-hour (fifteen miles-per-hour). Following
an automatic lock event, if the driver side front door
is opened first after the ignition is turned to the Off
position, all doors will be automatically unlocked.
²Turn Signal & Hazard Warning Lamp Con-
trol- The EMIC provides electronic turn and hazard
lamp request messages to the Front Control Module
(FCM) located on the Integrated Power Module (IPM)
for turn and hazard lamp control. The EMIC also
provides an audible click at one of two rates to emu-
late normal and bulb out turn or hazard flasher oper-
ation based upon electronic lamp outage messages
from the FCM, and provides an audible turn signal
on chime warning if a turn is signalled continuously
8J - 4 INSTRUMENT CLUSTERDR
INSTRUMENT CLUSTER (Continued)