2002 JEEP GRAND CHEROKEE WIRING

CONTROL/CENTRAL TIMER MODULE -
DESCRIPTION).
²Combination Flasher (Refer to 8 - ELECTRI-
CAL/LAMPS/LIGHTING - EXTERIOR/COMBINA-
TION FLASHER - DESCRIPTION).
²Door Ajar Switch (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - INTERIOR/DOOR AJAR
SWITCH - DESCRIPTION - DOOR AJAR SWITCH).
²Driver Cylinder Lock Switch (Refer to 8 - ELEC-
TRICAL/POWER LOCKS/DOOR CYLINDER LOCK/
UNLOCK SWITCH - DESCRIPTION).
²Hood Ajar Switch(Refer to 8 - ELECTRICAL/VE-
HICLE THEFT SECURITY/HOOD AJAR SWITCH -
DESCRIPTION).
²Horn Relay (Refer to 8 - ELECTRICAL/HORN/
HORN RELAY - DESCRIPTION).
²Liftgate Ajar Switch (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - INTERIOR/DOOR AJAR
SWITCH - DESCRIPTION - LIFTGATE AJAR
SWITCH).
²Liftgate Flip-Up Glass Ajar Switch(Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - INTERIOR/
DOOR AJAR SWITCH - DESCRIPTION - LIFTGATE
FLIP-UP GLASS AJAR SWITCH).
²Low Beam Headlamp Relay
²VTSS Indicator (Refer to 8 - ELECTRICAL/VE-
HICLE THEFT SECURITY/VTSS INDICATOR -
DESCRIPTION).
Certain functions and features of the VTSS rely
upon resources shared with or controlled by other
modules in the vehicle over the Programmable Com-
munications Interface (PCI) data bus network. The
other modules that may affect VTSS operation are:
²Driver Door Module (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/DOOR MOD-
ULE - DESCRIPTION).
²Passenger Door Module (Refer to 8 - ELECTRI-
CAL/ELECTRONIC CONTROL MODULES/DOOR
MODULE - DESCRIPTION).
DESCRIPTION - SENTRY KEY IMMOBILIZER
SYSTEM
Vehicles equipped with the Sentry Key Immobilizer
System (SKIS) can be identified by the presence of
an amber SKIS indicator in the instrument cluster
that will illuminate for about three seconds each
time the ignition switch is turned to the On position,
or by a gray molded rubber cap on the head of the
ignition key. Models not equipped with SKIS still
have a SKIS indicator in the cluster, but it will not
illuminate. Also, models not equipped with the SKIS
have a black molded rubber cap on the head of the
ignition key.
The SKIS includes the following major components,
which are described in further detail elsewhere in
this service manual:²Powertrain Control Module
²Sentry Key Immobilizer Module
²Sentry Key Transponder
²SKIS Indicator
Except for the Sentry Key transponders, which rely
upon Radio Frequency (RF) communication, hard
wired circuitry connects the SKIS components to the
electrical system of the vehicle.Refer to the appropri-
ate wiring information.
OPERATION
OPERATION - VEHICLE THEFT SECURITY
SYSTEM
The Vehicle Theft Security System (VTSS) is
divided into two basic subsystems: Vehicle Theft
Alarm (VTA) and Sentry Key Immobilizer System
(SKIS). The following are paragraphs that briefly
describe the operation of each of those two sub-
systems.
A Body Control Module (BCM) is used to control
and integrate many of the functions and features
included in the Vehicle Theft Security System
(VTSS). In the VTSS, the BCM receives inputs indi-
cating the status of the door ajar switches, the driver
cylinder lock switch, the ignition switch, the liftgate
ajar switches, the liftgate flip-up glass ajar switch,
the power lock switches and, in vehicles so equipped,
the hood ajar switch. The programming in the BCM
allows it to process the information from all of these
inputs and send control outputs to energize or de-en-
ergize the combination flasher, the horn relay (except
vehicles with the premium version of the VTA), and
the VTSS indicator. In addition, in vehicles built for
certain markets where premium versions of the VTA
is required, the BCM also exchanges messages with
the Intrusion Transceiver Module (ITM) over the Pro-
grammable Communications Interface (PCI) data
buss network to provide the features found in this
version of the VTA. The control of these inputs and
outputs are what constitute all of the features of the
VTSS. Following is information on the operation of
each of the VTSS features.
ENABLING
The BCM must have the VTSS function enabled in
order for the VTSS to perform as designed. The logic
in the BCM keeps its VTSS function dormant until it
is enabled using a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
PRE-ARMING
The VTA has a pre-arming sequence. Pre-arming
occurs when a door, the tailgate, or the flip-up glass
is open when the vehicle is locked using a power lock
8Q - 2 VEHICLE THEFT SECURITYWJ
VEHICLE THEFT SECURITY (Continued)

tion feature of the ITM can be disabled by depressing
the ªLockº button on the RKE transmitter three
times or cycling the key in the driver door cylinder
from the center to lock position within fifteen seconds
during VTA arming, while the security indicator is
still flashing rapidly. The VTA provides a single short
siren ªchirpº as an audible conformation that the
motion detect disable request has been received. The
ITM must be electronically enabled in order for the
intrusion alarm to perform as designed. The intru-
sion alarm function of the ITM is enabled on vehicles
equipped with this option at the factory, but a service
replacement ITM must be configured and enabled by
the dealer using the DRBIIItscan tool. Refer to the
appropriate diagnostic information.
OPERATION - SENTRY KEY IMMOBILIZER
SYSTEM
The Sentry Key Immobilizer System (SKIS) is
designed to provide passive protection against unau-
thorized vehicle use by disabling the engine after
about two seconds of running, whenever any method
other than a valid Sentry Key is used to start the
vehicle. The SKIS is considered a passive protection
system because it is always active when the ignition
system is energized and does not require any cus-
tomer intervention. The SKIS uses Radio Frequency
(RF) communication to obtain confirmation that the
key in the ignition switch is a valid key for operating
the vehicle. The microprocessor-based SKIS hard-
ware and software also uses messages to communi-
cate with other modules in the vehicle over the
Programmable Communications Interface (PCI) data
bus. (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/COMMUNICATION - OPERA-
TION).
Pre-programmed Sentry Key transponders are pro-
vided with the vehicle from the factory. Each Sentry
Key Immobilizer Module (SKIM) will recognize a
maximum of eight Sentry Keys. If the customer
would like additional keys other than those provided
with the vehicle, they may be purchased from any
authorized dealer. These additional keys must be pro-
grammed to the SKIM in the vehicle in order for the
system to recognize them as valid keys. This can be
done by the dealer using a DRBIIItscan tool or, if
Customer Learn programming is an available SKIS
feature in the market where the vehicle was pur-
chased, the customer can program the additional
keys, as long as at least two valid Sentry Keys are
already available. (Refer to 8 - ELECTRICAL/VEHI-
CLE THEFT SECURITY - STANDARD PROCE-
DURE - TRANSPONDER PROGRAMMING).
The SKIS performs a self-test each time the igni-
tion switch is turned to the On position, and will
store fault information in the form of DiagnosticTrouble Codes (DTC's) if a system malfunction is
detected. Refer to the appropriate diagnostic informa-
tion.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - VEHICLE THEFT
SECURITY SYSTEM
The VTSS-related hard wired inputs to and out-
puts from the Body Control Module (BCM), the
Driver Door Module (DDM), or the Passenger Door
Module (PDM) may be diagnosed and tested using
conventional diagnostic tools and procedures. Refer
to the appropriate wiring information.
However, conventional diagnostic methods may not
prove conclusive in the diagnosis of the BCM, the
DDM, the PDM, or the Programmable Communica-
tions Interface (PCI) data bus network. In order to
obtain conclusive testing of the VTSS, the BCM, the
DDM, the PDM, and the PCI data bus network must
also be checked. The most reliable, efficient, and
accurate means to diagnose the VTSS requires the
use of a DRBIIItscan tool and the appropriate diag-
nostic information.
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.
8Q - 4 VEHICLE THEFT SECURITYWJ
VEHICLE THEFT SECURITY (Continued)

DIAGNOSIS AND TESTING - SENTRY KEY
IMMOBILIZER SYSTEM
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.
SENTRY KEY IMMOBILIZER SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
SKIS INDICATOR FAILS TO
LIGHT DURING BULB TEST1. Bulb faulty. 1. Perform the instrument cluster actuator test.
(Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING -
ACTUATOR TEST). Replace the faulty bulb, if
required.
2. Fuse faulty. 2. Check the SKIM fused B(+) fuse and the fused
ignition switch output (st-run) fuse in the JB.
Replace fuses, if required.
3. Ground path faulty. 3. Check for continuity to ground at the connector
for the SKIM. Repair wiring, if required.
4. Battery feed faulty. 4. Check for battery current at the connector for
the SKIM. Repair wiring, if required.
5. Ignition feed faulty. 5. Check for battery current at the connector for
the SKIM with the ignition switch in the On
position. Repair wiring, if required.
SKIS INDICATOR FLASHES
FOLLOWING BULB TEST1. Invalid key in ignition
switch lock cylinder.1. Replace the key with a known valid key.
2. Key-related fault. 2. Use a DRBIIITscan tool and the appropriate
diagnostic information for further diagnosis.
SKIS INDICATOR LIGHTS
SOLID FOLLOWING BULB
TEST1. SKIS system malfunction/
fault detected.1. Use a DRBIIITscan tool and the appropriate
diagnostic information for further diagnosis.
2. SKIS system inoperative. 2. Use a DRBIIITscan tool and the appropriate
diagnostic information for further diagnosis.
SKIS INDICATOR FAILS TO LIGHT DURING BULB TEST
If the Sentry Key Immobilizer System (SKIS) indi-
cator in the instrument cluster fails to illuminate for
about three seconds after the ignition switch is
turned to the On position (bulb test), perform the
instrument cluster actuator test. (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING - ACTUATOR TEST). If the bulb
fails to operate during the actuator test, replace the
bulb. If the SKIS indicator still fails to light during
the bulb test, a wiring problem resulting in the loss
of battery current or ground to the Sentry Key Immo-
bilizer Module (SKIM) should be suspected, and thefollowing procedure should be used for diagnosis.
Refer to the appropriate wiring information.
NOTE: The following tests may not prove conclu-
sive in the diagnosis of this system. The most reli-
able, efficient, and accurate means to diagnose the
Sentry Key Immobilizer System requires the use of
a DRBIIITscan tool. Refer to the appropriate diag-
nostic information.
(1) Check the fused B(+) fuse in the Junction
Block (JB). If OK, go to Step 2. If not OK, repair the
shorted circuit or component and replace the faulty
fuse.
WJVEHICLE THEFT SECURITY 8Q - 5
VEHICLE THEFT SECURITY (Continued)

cylinder lock switches are driven by the key lock cyl-
inders and contain two internal resistors. One resis-
tor value is used for the Lock position, and one for
the Unlock position.
The door cylinder lock switches cannot be adjusted
or repaired and, if faulty or damaged, they must be
replaced.
OPERATION
The door cylinder lock switches are actuated by the
key lock cylinder when the key is inserted in the lock
cylinder and turned to the lock or unlock positions.
The door cylinder lock switch close a circuit between
the door lock switch ground circuit and the left or
right cylinder lock switch mux circuits through one of
two internal resistors for the Driver Door Module
(DDM) when either front door key lock cylinder is in
the Lock, or Unlock positions. The DDM reads the
switch status through an internal pull-up, then uses
this information as an input for the Vehicle Theft
Security System (VTSS) operation.
The door cylinder lock switches and circuits can be
diagnosed using conventional diagnostic tools and
methods.
DIAGNOSIS AND TESTING - DOOR CYLINDER
LOCK SWITCH
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.(1) Disconnect the door cylinder lock switch pigtail
wire connector from the door wire harness connector.
(2) Using a ohmmeter, check the switch resistance
checks between the two terminals in the door cylin-
der lock switch pigtail wire connector. Actuate the
switch by rotating the key in the door lock cylinder
to test for the proper resistance values in each of the
two switch positions, as shown in the Door Cylinder
Lock Switch Test table.
DOOR CYLINDER LOCK SWITCH TEST
Switch Position Resistance
( 10%)
Left Side Right Side
Lock (Clockwise) Unlock
(Counterclockwise)473 Ohms
Unlock
(Counterclockwise)Lock (Clockwise) 1.994
Kilohms
(3) If a door cylinder lock switch fails either of the
resistance tests, replace the faulty switch.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the outside door handle unit from the
outer door panel. (Refer to 23 - BODY/DOOR -
FRONT/EXTERIOR HANDLE - REMOVAL).
(3) Remove the retainer clip from the pin on the
back of the door lock cylinder (Fig. 2).
(4) Remove the lock lever from the pin on the back
of the door lock cylinder.
Fig. 1 DOOR CYLINDER LOCK SWITCH
1 - SWITCH
2 - OUTSIDE DOOR HANDLE
3 - DOOR LOCK CYLINDER
Fig. 2 LOCK CYLINDER LEVER RETAINER RE
1 - LEVER
2 - RETAINER
3 - LOCK CYLINDER
4 - SWITCH
5 - PLIERS
6 - OUTSIDE DOOR HANDLE
8Q - 8 VEHICLE THEFT SECURITYWJ
DOOR CYLINDER LOCK SWITCH (Continued)

(5) Remove the door cylinder lock switch from the
back of the lock cylinder.
INSTALLATION
(1) Position the door cylinder lock switch onto the
back of the lock cylinder with its pigtail wire harness
oriented toward the bottom (Fig. 2).
(2) Position the lock lever onto the pin on the back
of the door lock cylinder with the lever oriented
toward the rear.
(3) Install the retainer clip onto the pin on the
back of the door lock cylinder. Be certain that the
center tab of the retainer is engaged in the retention
hole on the lock lever.
(4) Reinstall the outside door handle unit onto the
outer door panel. (Refer to 23 - BODY/DOOR -
FRONT/EXTERIOR HANDLE - INSTALLATION).
(5) Reconnect the battery negative cable.
HOOD AJAR SWITCH
DESCRIPTION
The hood ajar switch is a self-adjusting, normally
closed, single pole, double throw momentary switch
that is used only on vehicles built for sale in certain
international markets where it is required equipment
(Fig. 3). The mounting bracket is fastened to the left
inner fender. A molded plastic striker with three inte-
gral retainers is secured to the underside of the hood
panel inner reinforcement to actuate the switch
plunger as the hood panel is closed.The switchreceives a path to ground through the left inner
fender shield in the engine compartment.
The hood ajar switch adjusts itself as the striker
pushes the switch body down through the switch
when the hood panel is closed after the initial instal-
lation. This self-adjustment feature is only functional
the first time the hood is closed following installa-
tion. If the switch requires adjustment following the
initial installation, the switch must be replaced.
OPERATION
The normally closed hood ajar switch is normally
held open when the hood panel is closed and latched.
When the hood is opened, the switch plunger extends
from the switch body and the switch contacts are
closed. The hood ajar switch is connected in series
between ground and the hood ajar switch sense input
of the Body Control Module (BCM). The BCM uses
an internal resistor pull up to monitor the state of
the hood ajar switch contacts. The hood ajar switch
can be diagnosed using conventional diagnostic tools
and methods.
DIAGNOSIS AND TESTING - HOOD AJAR
SWITCH
The diagnosis found here addresses an inoperative
hood ajar switch. If the problem being diagnosed is
related to hood ajar switch accuracy, be certain to
confirm that the problem is not an improperly
adjusted hood ajar switch. If no hood ajar switch
adjustment problem is found, the following procedure
will help to locate a short or open in the hood ajar
switch circuit. Refer to the appropriate wiring infor-
mation.
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 hood ajar switch. Check for
continuity between the harness ground circuit a good
ground. There should be continuity. If OK, go to Step
2. If not OK, repair the open ground circuit to
ground.
Fig. 3 Hood Ajar Switch
1 - SWITCH
2 - STUD (2)
3 - BRACKET
4 - FENDER
5 - CONNECTOR
6 - NUT (2)
WJVEHICLE THEFT SECURITY 8Q - 9
DOOR CYLINDER LOCK SWITCH (Continued)

(2) Check for continuity between the two terminals
of the hood ajar switch. There should be continuity
with the switch plunger extended, and no continuity
with the switch plunger depressed. If OK, go to Step
3. If not OK, replace the faulty hood ajar switch.
(3) Disconnect the instrument panel wire harness
connector from the Body Control Module (BCM).
Check for continuity between the hood ajar switch
sense circuit of the hood ajar switch and a good
ground. There should be no continuity. If OK, go to
Step 4. If not OK, repair the shorted hood ajar switch
sense circuit between the hood ajar switch and the
BCM.
(4) Check for continuity between the hood ajar
switch sense circuit and the instrument panel wire
harness connector for the BCM. There should be con-
tinuity. If OK, proceed to diagnosis of the Vehicle
Theft Security System (VTSS). (Refer to 8 - ELEC-
TRICAL/VEHICLE THEFT SECURITY - DIAGNO-
SIS AND TESTING). If not OK, repair the open hood
ajar switch sense circuit between the hood ajar
switch and the BCM.
REMOVAL
REMOVAL - HOOD AJAR SWITCH
(1) Open the hood.
(2) Disconnect and isolate the battery negative
cable.
(3) Squeeze the two switch latch tabs together and
pull the switch upward (Fig. 3)
(4) Disconnect the wiring harness connector.
(5) Remove the hood ajar switch from the mount-
ing bracket.
REMOVAL - HOOD AJAR SWITCH BRACKET
(1) Remove the hood ajar switch from the mount-
ing bracket. (Refer to 8 - ELECTRICAL/VEHICLE
THEFT SECURITY/HOOD AJAR SWITCH -
REMOVAL).
(2) Remove the two nuts that secure the hood ajar
switch bracket to the left inner fender (Fig. 3)
(3) Remove the hood ajar switch bracket from the
studs on the left inner fender.
REMOVAL - HOOD AJAR SWITCH STRIKER
(1) Open the hood.
(2) Using a trim stick or another suitable wide
flat-blade tool, gently raise the hood ajar switch
striker away from the inner hood panel reinforce-
ment, and remove. (Fig. 4).
INSTALLATION
INSTALLATION - HOOD AJAR SWITCH
(1) Position the hood ajar switch into the hole in
the mounting bracket (Fig. 3)
(2) Reconnect the wiring harness connector.
(3) Press the switch downward into the mounting
bracket until the latch tabs lock it into place.
(4) Reconnect the battery negative cable.
(5) Close and latch the hood.
INSTALLATION - HOOD AJAR SWITCH
BRACKET
(1) Position the hood ajar switch bracket onto the
studs on the left inner fender (Fig. 3)
(2) Install and tighten the two nuts. Tighten the
nuts to 11.8 N´m (105 in. lbs.).
(3) Reinstall the hood ajar switch into the mount-
ing bracket. (Refer to 8 - ELECTRICAL/VEHICLE
THEFT SECURITY/HOOD AJAR SWITCH -
INSTALLATION).
Fig. 4 Hood Ajar Switch Striker
1 - REINFORCEMENT
2 - STRIKER
3 - HOOD
8Q - 10 VEHICLE THEFT SECURITYWJ
HOOD AJAR SWITCH (Continued)

message inputs to and outputs from the alarm siren
module requires the use of a DRBIIItscan tool.
Refer to the appropriate diagnostic information.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the alarm siren module wiring har-
ness connector. (Fig. 9).
(3) Remove the screws that secure the alarm siren
module to the left frame rail.
(4) Remove the alarm siren module.
INSTALLATION
(1) Position the alarm siren module on to the left
frame rail. (Fig. 9).
(2) Install and tighten the screws that secure the
alarm siren moduleto the frame rail. Tighten the
screws to 6 N´m (50 in. lbs.).
(3) Reconnect the alarm siren module wiring har-
ness connector.
(4) Reconnect the battery negative cable.
NOTE: If the alarm siren module has been replaced
with a new unit, the new unit MUST be configured
in the Intrusion Transceiver Module (ITM) before the
Vehicle Theft Security System can operate as
designed. The use of a DRBIIITscan tool is requiredto configure the alarm siren module settings in the
ITM. Refer to the appropriate diagnostic informa-
tion.
SKIS INDICATOR LAMP
DESCRIPTION
A Sentry Key Immobilizer System (SKIS) indicator
lamp is standard equipment on all instrument clus-
ters, but is only functional on vehicles equipped with
the optional SKIS. The amber SKIS indicator lamp is
located to the right of the oil pressure gauge.
OPERATION
The Sentry Key Immobilizer System (SKIS) indica-
tor lamp gives an indication to the vehicle operator of
the status of the SKIS. This lamp is controlled by a
transistor on the instrument cluster circuit board
based upon messages received by the cluster from
the Sentry Key Immobilizer Module (SKIM) over the
Programmable Communications Interface (PCI) data
bus. The SKIS indicator lamp bulb receives battery
current on the instrument cluster circuit board
through the fused ignition switch output (st-run) cir-
cuit whenever the ignition switch is in the On or
Start positions. The lamp bulb only illuminates when
it is provided a path to ground by the instrument
cluster transistor. The instrument cluster will turn
on the SKIS indicator lamp for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position, the SKIM tells the cluster
to illuminate the lamp for about three seconds.
²SKIS Lamp-On Message- Each time the clus-
ter receives a SKIS lamp-on message from the SKIM,
the lamp will be illuminated. The lamp can be
flashed on and off, or illuminated solid, as dictated
by the message from the SKIM. For more informa-
tion on the SKIS and the SKIS lamp control param-
eters, (Refer to 8 - ELECTRICAL/VEHICLE THEFT
SECURITY - OPERATION - SENTRY KEY IMMO-
BILIZER SYSTEM). The lamp remains illuminated
until the cluster receives a lamp-off message from
the SKIM or until the ignition switch is turned to the
Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the lamp will be turned on
for the duration of the test to confirm the functional-
ity of the lamp and the cluster.
The SKIM performs a self-test each time the igni-
tion switch is turned to the On position to decide
whether the system is in good operating condition.
The SKIM then sends a message to the instrument
cluster. If the SKIS indicator lamp fails to light dur-
ing the bulb test, replace the bulb. For further diag-
nosis of the SKIS indicator lamp or the instrument
Fig. 9 Siren Remove/Install
1 - SIREN
2 - FRAME
8Q - 14 VEHICLE THEFT SECURITYWJ
SIREN (Continued)

OPERATION
The Vehicle Theft Security System (VTSS) indica-
tor gives a visible indication of the VTSS arming sta-
tus. One side of Light-Emittiong Diode (LED) in the
VTSS indicator is connected to unswitched battery
current through a fused B(+) circuit and a fuse in the
Junction Block (JB). The other side of the LED is
hard wired to the Body Control Module (BCM), which
controls the operation of the VTSS indicator by pull-
ing this side of the LED circuit to ground. When the
VTSS arming is in progress, the BCM will flash the
LED rapidly on and off for about fifteen seconds.
When the VTSS has been successfully armed, the
BCM will flash the LED on and off continually at a
much slower rate until the VTSS has been disarmed.
The VTSS indicator can be diagnosed using conven-
tional diagnostic tools and methods.
DIAGNOSIS AND TESTING - VTSS INDICATOR
The diagnosis found here addresses an inoperative
Vehicle Theft Security System (VTSS) indicator con-
dition. If the problem being diagnosed is related to
indicator accuracy, be certain to confirm that the
problem is with the indicator and not with an inop-
erative VTSS. (Refer to 8 - ELECTRICAL/VEHICLE
THEFT SECURITY - DIAGNOSIS AND TESTING -
VEHICLE THEFT SECURITY SYSTEM). If no VTSS
problem is found, the following procedure will help to
locate a short or open in the VTSS indicator control
circuit. Refer to the appropriate wiring information.
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) Check the fused B(+) fuse in the Junction
Block (JB). If OK, go to Step 2. If not OK, repair the
shorted circuit or component and replace the faulty
fuse.
(2) Check for battery voltage at the fused B(+) fuse
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).
(3) Disconnect and isolate the battery negative
cable. Disconnect the instrument panel wire harness
connector for the automatic headlamp light sensor/
VTSS indicator from the automatic headlamp light
sensor/VTSS indicator pigtail wire connector. Recon-
nect the battery negative cable. Check for battery
voltage at the fused B(+) circuit cavity of the instru-
ment panel wire harness connector for the automatic
headlamp light sensor/VTSS indicator. If OK, go to
Step 4. If not OK, repair the open fused B(+) circuit
between the VTSS indicator and the JB.
(4) Disconnect and isolate the battery negative
cable. Disconnect the instrument panel wire harness
connector for the JB from the JB connector recepta-
cle. Check for continuity between the VTSS indicator
driver circuit cavity of the instrument panel wire
harness connector for the automatic headlamp light
sensor/VTSS indicator and a good ground. There
should be no continuity. If OK, go to Step 5. If not
OK, repair the shorted VTSS indicator driver circuit
between the VTSS indicator and the JB.
(5) Check for continuity between the VTSS indica-
tor driver circuit of the instrument panel wire har-
ness connector for the automatic headlamp light
sensor/VTSS indicator and the instrument panel wire
harness connector for the JB. There should be conti-
nuity. If OK, replace the faulty VTSS indicator. If not
OK, repair the open VTSS indicator driver circuit
between the VTSS indicator and the JB.
8Q - 16 VEHICLE THEFT SECURITYWJ
VTSS INDICATOR (Continued)