2002 JEEP LIBERTY Speed control system

message from the SKIM or until the ignition switch
is turned to the Off position, whichever occurs first.
²Communication Error- If the cluster receives
no SKIS lamp-on or lamp-off messages from the
SKIM for twenty consecutive seconds, the SKIS indi-
cator is illuminated by the instrument cluster. The
indicator remains controlled and illuminated by the
cluster until a valid SKIS lamp-on or lamp-off mes-
sage is received from the SKIM.
²Actuator Test- Each time the cluster is put
through the actuator test, the SKIS indicator will be
turned on, then off again during the bulb check por-
tion of the test to confirm the functionality of the
LED and the cluster control circuitry.
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
and whether a valid key is present in the ignition
lock cylinder. The SKIM then sends the proper SKIS
lamp-on or lamp-off messages to the instrument clus-
ter. For further diagnosis of the SKIS indicator or the
instrument cluster circuitry that controls the indica-
tor, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). If the
instrument cluster flashes the SKIS indicator upon
ignition On, or turns on the SKIS indicator solid
after the bulb test, it indicates that a SKIS malfunc-
tion has occurred or that the SKIS is inoperative. For
proper diagnosis of the SKIS, the PCI data bus, or
the electronic message inputs to the instrument clus-
ter that control the SKIS indicator, a DRBIIItscan
tool is required. Refer to the appropriate diagnostic
information.
SPEEDOMETER
DESCRIPTION
A speedometer is standard equipment on all instru-
ment clusters. The speedometer is located to the
right of the tachometer in the instrument cluster.
The speedometer consists of a movable gauge needle
or pointer controlled by the instrument cluster cir-
cuitry, and a fixed 255 degree primary scale on the
gauge dial face that reads left-to-right either from 0
to 120 mph, or from 0 to 240 km/h, depending upon
the market for which the vehicle is manufactured.
Most models also have a smaller secondary inner
scale on the gauge dial face that provides the equiv-
alent opposite measurement units from the primary
scale. Text appearing on the cluster overlay just
below the hub of the speedometer needle abbreviates
the unit of measure for the primary scale first (i.e.:
MPH or km/h), followed by the unit of measure for
the secondary scale (i.e.: MPH or km/h). The speed-
ometer graphics are dark blue (primary scale) andlight blue (secondary scale) against a beige field,
making them clearly visible within the instrument
cluster in daylight. When illuminated from behind by
the panel lamps dimmer controlled cluster illumina-
tion lighting with the exterior lamps turned On, both
the dark blue and light blue graphics retain their
blue colors. The orange gauge needle is internally
illuminated. Gauge illumination is provided by
replaceable incandescent bulb and bulb holder units
located on the instrument cluster electronic circuit
board. The speedometer is serviced as a unit with the
instrument cluster.
OPERATION
The speedometer gives an indication to the vehicle
operator of the vehicle road speed. This gauge is con-
trolled by the instrument cluster electronic circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Program-
mable Communications Interface (PCI) data bus. The
speedometer is an air core magnetic unit that
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (run-start) circuit whenever the igni-
tion switch is in the On or Start positions. The clus-
ter is programmed to move the gauge needle back to
the low end of the scale after the ignition switch is
turned to the Off position. The instrument cluster
circuitry controls the gauge needle position and pro-
vides the following features:
²Vehicle Speed Message- Each time the clus-
ter receives a vehicle speed message from the PCM it
will calculate the correct vehicle speed reading and
position the gauge needle at that speed position on
the gauge scale. The cluster will receive a new vehi-
cle speed message and reposition the gauge pointer
accordingly about every 86 milliseconds. The gauge
needle will continue to be positioned at the actual
vehicle speed position on the gauge scale until the
ignition switch is turned to the Off position.
²Communication Error- If the cluster fails to
receive a speedometer message, it will hold the gauge
needle at the last indication for about six seconds, or
until the ignition switch is turned to the Off position,
whichever occurs first. If a new speed message is not
received after about six seconds, the gauge needle
will return to the far left (low) end of the scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept to several calibration points on the gauge scale
in sequence in order to confirm the functionality of
the gauge and the cluster control circuitry.
The PCM continually monitors the vehicle speed
information received from the Body Control Module
(BCM) to determine the vehicle road speed, then
8J - 32 INSTRUMENT CLUSTERKJ
SKIS INDICATOR (Continued)

ible when it is not illuminated. An amber Light
Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the ªTRANS
TEMPº text to appear in amber through the translu-
cent outer layer of the overlay when the indicator is
illuminated from behind by the LED, which is sol-
dered onto the instrument cluster electronic circuit
board. The transmission over-temperature indicator
is serviced as a unit with the instrument cluster.
OPERATION
The transmission over-temperature indicator gives
an indication to the vehicle operator when the trans-
mission fluid temperature is excessive, which may
lead to accelerated transmission component wear or
failure. This indicator is controlled by a transistor on
the instrument cluster electronic circuit board based
upon the cluster programming and electronic mes-
sages received by the cluster from the Powertrain
Control Module (PCM) over the Programmable Com-
munications Interface (PCI) data bus. The transmis-
sion over-temperature indicator Light Emitting Diode
(LED) is completely controlled by the instrument
cluster logic circuit, and that logic will only allow
this indicator to operate when the instrument cluster
receives a battery current input on the fused ignition
switch output (run-start) circuit. Therefore, the LED
will always be off when the ignition switch is in any
position except On or Start. The LED only illumi-
nates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the transmission over-temperature indi-
cator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the transmission over-tem-
perature indicator is illuminated for about three sec-
onds as a bulb test.
²Trans Over-Temp Lamp-On Message- Each
time the cluster receives a trans over-temp lamp-on
message from the PCM indicating that the transmis-
sion fluid temperature is 135É C (275É F) or higher,
the indicator will be illuminated. The indicator
remains illuminated until the cluster receives a trans
over-temp lamp-off message from the PCM, 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 trans over-temp indi-
cator will be turned on, then off again during the
bulb check portion of the test to confirm the function-
ality of the LED and the cluster control circuitry.
The PCM continually monitors the transmission
temperature sensor to determine the transmission
operating condition. The PCM then sends the proper
trans over-temp lamp-on and lamp-off messages to
the instrument cluster. If the instrument clusterturns on the transmission over-temperature indicator
due to a high transmission oil temperature condition,
it may indicate that the transmission and/or the
transmission cooling system are being overloaded or
that they require service. For further diagnosis of the
transmission over-temperature indicator or the
instrument cluster circuitry that controls the indica-
tor, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). For
proper diagnosis of the transmission temperature
sensor, the PCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the transmission over-temperature indicator, a
DRBIIItscan tool is required. Refer to the appropri-
ate diagnostic information.
TURN SIGNAL INDICATOR
DESCRIPTION
Two turn signal indicators, one right and one left,
are standard equipment on all instrument clusters.
The turn signal indicators are located near the upper
edge of the instrument cluster, between the speedom-
eter and the tachometer. Each turn signal indicator
consists of a stencil-like cutout of the International
Control and Display Symbol icon for ªTurn Warningº
in the opaque layer of the instrument cluster overlay.
The dark outer layer of the overlay prevents these
icons from being clearly visible when they are not
illuminated. A green Light-Emitting Diode (LED)
behind each cutout in the opaque layer of the cluster
overlay causes the indicator to appear in green
through the translucent outer layer of the overlay
when it is illuminated from behind by the LED,
which is soldered onto the instrument cluster elec-
tronic circuit board. The turn signal indicators are
serviced as a unit with the instrument cluster.
OPERATION
The turn signal indicators give an indication to the
vehicle operator that the turn signal (left or right
indicator flashing) or hazard warning (both left and
right indicators flashing) have been selected and are
operating. These indicators are controlled by two
individual hard wired inputs from the combination
flasher circuitry within the hazard switch to the
instrument cluster electronic circuit board. Each turn
signal indicator Light Emitting Diode (LED) is
grounded on the instrument cluster electronic circuit
board at all times; therefore, these indicators remain
functional regardless of the ignition switch position.
Each LED will only illuminate when it is provided
battery current by the combination flasher circuitry
of the hazard switch.
8J - 34 INSTRUMENT CLUSTERKJ
TRANS TEMP INDICATOR (Continued)

The turn signal indicators are connected in parallel
with the other turn signal circuits. This arrangement
allows the turn signal indicators to remain func-
tional, regardless of the condition of the other cir-
cuits in the turn signal and hazard warning systems.
The combination flasher outputs of the hazard switch
to the instrument cluster turn signal indicator inputs
can be diagnosed using conventional diagnostic tools
and methods. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/HAZARD SWITCH -
DESCRIPTION) for more information on the combi-
nation flasher and hazard switch operation.
WAIT-TO-START INDICATOR
DESCRIPTION
A wait-to-start indicator is only found in the
instrument clusters of vehicles equipped with an
optional diesel engine. The wait-to-start indicator is
located above the fuel gauge and to the left of the
tachometer in the instrument cluster. The wait-to-
start indicator consists of a stencil-like cutout of the
International Control and Display Symbol icon for
ªDiesel Preheatº in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents the indicator from being clearly vis-
ible when it is not illuminated. An amber Light
Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
in amber through the translucent outer layer of the
overlay when it is illuminated from behind by the
LED, which is soldered onto the instrument cluster
electronic circuit board. The wait-to-start indicator is
serviced as a unit with the instrument cluster.
OPERATION
The wait-to-start indicator gives an indication to
the vehicle operator when the diesel engine glow
plugs are energized in their pre-heat operating mode.
This indicator is controlled by a transistor on the
instrument cluster electronic circuit board based
upon the cluster programming and electronic mes-
sages received by the cluster from the Powertrain
Control Module (PCM) over the Programmable Com-
munications Interface (PCI) data bus. The wait-to-
start indicator Light Emitting Diode (LED) is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster receives a bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster willturn on the wait-to-start indicator for the following
reasons:
²Wait-To-Start Lamp-On Message- Each time
the cluster receives a wait-to-start lamp-on message
from the PCM indicating the glow plugs are heating
and the driver must wait to start the engine, the
wait-to-start indicator will be illuminated. The indi-
cator remains illuminated until the cluster receives a
wait-to-start lamp-off message, 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 wait-to-start indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The PCM continually monitors the ambient tem-
perature and the glow plug pre-heater circuits to
determine how long the glow plugs must be heated in
the pre-heat operating mode. The PCM then sends
the proper wait-to-start lamp-on and lamp-off mes-
sages to the instrument cluster. For further diagnosis
of the wait-to-start indicator or the instrument clus-
ter circuitry that controls the indicator, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). For proper diagnosis of the
glow plug pre-heater control circuits, the PCM, the
PCI data bus, or the electronic message inputs to the
instrument cluster that control the wait-to-start indi-
cator, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
WASHER FLUID INDICATOR
DESCRIPTION
A washer fluid indicator is standard equipment on
all instrument clusters. The washer fluid indicator
consists of the text ªlowashº, which appears in place
of the odometer/trip odometer information in the Vac-
uum-Fluorescent Display (VFD) of the instrument
cluster. The VFD is part of the cluster electronic cir-
cuit board, and is visible through a cutout located
near the lower edge of the speedometer dial face in
the instrument cluster. The dark outer layer of the
overlay prevents the VFD from being clearly visible
when it is not illuminated. The text message
ªlowashº appears in the same blue-green color and at
the same lighting level as the odometer/trip odometer
information through the translucent outer layer of
the overlay when it is illuminated by the instrument
cluster electronic circuit board. The washer fluid
indicator is serviced as a unit with the instrument
cluster.
KJINSTRUMENT CLUSTER 8J - 35
TURN SIGNAL INDICATOR (Continued)

OPERATION
The washer fluid indicator gives an indication to
the vehicle operator that the fluid level in the washer
reservoir is low. This indicator is controlled by the
instrument cluster electronic circuit board based
upon cluster programming and a hard wired input
received by the cluster from the washer fluid level
switch mounted on the washer reservoir. The washer
fluid indicator function of the Vacuum Fluorescent
Display (VFD) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the LED will always be off when the ignition switch
is in any position except On or Start. The instrument
cluster will turn on the washer fluid indicator for the
following reasons:
²Washer Fluid Level Switch Input- Each time
the cluster detects ground on the low washer fluid
sense circuit (washer fluid level switch closed =
washer fluid level low) the cluster applies an algo-
rithm to confirm that the input is correct and not the
result of fluid sloshing in the washer reservoir. The
cluster tests the status of the circuit about seven mil-
liseconds after ignition On, and about once every sec-
ond thereafter, then uses an internal counter to
count up or down. When the counter accumulates
thirty ground inputs on the circuit, the washer fluid
indicator will be illuminated. If the vehicle is not
moving when the washer fluid level switch input
counter reaches thirty, the VFD will repeatedly and
sequentially cycle its indication in two second inter-
vals with the odometer/trip odometer information,
the low washer fluid warning, and any other active
warnings including: door ajar, gate ajar, and glass
ajar. If the vehicle is moving, or once the cluster of a
non-moving vehicle receives an electronic vehicle
speed message from the Powertrain Control Module
(PCM) indicating a speed greater than zero, the
warning sequence will consist of three complete dis-
play cycles, then revert to only the odometer/trip
odometer display. Once the washer fluid indicator
warning has completed, the washer fluid indicator is
extinguished and will not repeat until the ignition
switch is cycled.
The instrument cluster continually monitors the
washer fluid level switch in the washer reservoir to
determine the status of the washer fluid level. For
further diagnosis of the washer fluid indicator or the
instrument cluster circuitry that controls the indica-
tor, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). The
washer fluid level switch and circuits can be diag-
nosed using conventional diagnostic tools and meth-
ods. The washer fluid level switch also features a 3.3kilohm diagnostic resistor connected in parallel
between the switch input and output to provide the
cluster with verification that the low washer fluid
sense circuit is not open or shorted. This input can
be monitored using a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
DIAGNOSIS AND TESTING - WASHER FLUID
INDICATOR
The diagnosis found here addresses an inoperative
washer fluid indicator condition. If the problem being
diagnosed is related to indicator accuracy, be certain
to confirm that the problem is with the indicator or
washer fluid level switch input and not with a dam-
aged or empty washer fluid reservoir, or inoperative
instrument cluster indicator control circuitry. Inspect
the washer fluid reservoir for proper fluid level and
signs of damage or distortion that could affect
washer fluid level switch performance and perform
the instrument cluster actuator test before you pro-
ceed with the following diagnosis. If no washer fluid
reservoir or instrument cluster control circuitry prob-
lem is found, the following procedure will help to
locate a short or open in the washer fluid switch
sense circuit. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
INDICATOR DOES NOT ILLUMINATE WITH WASHER
RESERVOIR EMPTY
(1) Disconnect and isolate the battery negative
cable. Disconnect the headlamp and dash wire har-
ness connector for the washer fluid level switch from
the washer fluid level switch connector receptacle.
Check for continuity between the ground circuit cav-
8J - 36 INSTRUMENT CLUSTERKJ
WASHER FLUID INDICATOR (Continued)

ity of the headlamp and dash wire harness connector
for the washer fluid level switch and a good ground.
There should be continuity. If OK, go to Step 2. If not
OK, repair the open ground circuit to ground (G111)
as required.
(2) Remove the instrument cluster from the instru-
ment panel. Check for continuity between the washer
fluid sense circuit cavities of the headlamp and dash
wire harness connector for the washer fluid level
switch and the instrument panel wire harness con-
nector (Connector C2) for the instrument cluster. If
OK, replace the faulty washer fluid level switch. If
not OK, repair the open washer fluid switch sense
circuit between the washer fluid level switch and the
instrument cluster as required.
INDICATOR STAYS ILLUMINATED WITH WASHER
RESERVOIR FULL
(1) Disconnect and isolate the battery negative
cable. Disconnect the headlamp and dash wire har-
ness connector for the washer fluid level switch from
the washer fluid level switch connector receptacle.
Check for continuity between the ground circuit ter-
minal and the washer fluid sense terminal in the
washer fluid level switch connector receptacle. There
should be no continuity. If OK, go to Step 2. If not
OK, replace the faulty washer fluid level switch.
(2) Remove the instrument cluster from the instru-
ment panel. Check for continuity between the washer
fluid sense circuit cavity of the headlamp and dash
wire harness connector for the washer fluid level
switch and a good ground. There should be no conti-
nuity. If not OK, repair the shorted washer fluid
switch sense circuit between the washer fluid level
switch and the instrument cluster as required.
WATER-IN-FUEL INDICATOR
DESCRIPTION
A water-in-fuel indicator is only found in the
instrument clusters of vehicles equipped with an
optional diesel engine. The water-in-fuel indicator is
located above the coolant temperature gauge and to
the right of the speedometer in the instrument clus-
ter. The water-in-fuel indicator consists of a stencil-
like cutout of the International Control and Display
Symbol icon for ªWater In Fuelº in the opaque layer
of the instrument cluster overlay. The dark outer
layer of the overlay prevents the indicator from being
clearly visible when it is not illuminated. A red Light
Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
in red through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. Thewater-in-fuel indicator is serviced as a unit with the
instrument cluster.
OPERATION
The water-in-fuel indicator gives an indication to
the vehicle operator when there is excessive water in
the fuel system. This indicator is controlled by a
transistor on the instrument cluster electronic circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Program-
mable Communications Interface (PCI) data bus. The
water-in-fuel indicator Light Emitting Diode (LED) is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster receives a bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the water-in-fuel indicator for the following
reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the water-in-fuel indicator
is illuminated for about three seconds as a bulb test.
²Water-In-Fuel Lamp-On Message- Each time
the cluster receives a water-in-fuel lamp-on message
from the PCM indicating there is excessive water in
the diesel fuel system, the water-in-fuel indicator will
be illuminated. The indicator remains illuminated
until the cluster receives a water-in-fuel lamp-off
message, 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 water-in-fuel indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The PCM continually monitors the water-in-fuel
sensor to determine whether there is excessive water
in the diesel fuel. The PCM then sends the proper
water-in-fuel lamp-on and lamp-off messages to the
instrument cluster. For further diagnosis of the
water-in-fuel indicator or the instrument cluster cir-
cuitry that controls the indicator, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). For proper diagnosis of the water-
in-fuel-sensor, the PCM, the PCI data bus, or the
electronic message inputs to the instrument cluster
that control the water-in-fuel indicator, a DRBIIIt
scan tool is required. Refer to the appropriate diag-
nostic information.
KJINSTRUMENT CLUSTER 8J - 37
WASHER FLUID INDICATOR (Continued)

trols for both the exterior and interior lighting sys-
tems.
²Park Lamp Relay- A park lamp relay is
located in the Junction Block (JB) of all vehicles.
²Rear Fog Lamp Relay- Vehicles manufac-
tured for certain markets where rear fog lamps are
required equipment have a rear fog lamp relay
located in the Junction Block (JB).
²Trailer Tow Adapter- Vehicles equipped with
a factory-installed trailer towing package have an
adapter provided that adapts the factory-installed
heavy duty 7-way trailer tow connector to a conven-
tional 4-way light duty connector.
²Trailer Tow Connector- Vehicles equipped
with a factory-installed trailer towing package have a
heavy duty 7-way trailer tow connector installed in a
bracket on the trailer hitch receiver.
²Trailer Tow Relays- Vehicles equipped with a
factory-installed trailer towing package have a con-
nector bank containing four relays located behind the
right quarter trim panel and over the right rear
wheel housing. The four relays are used to supply
fused ignition switch output (run), brake lamps, right
turn signal, and left turn signal outputs to a trailer
through the trailer tow wiring and connectors.
Hard wired circuitry connects the exterior lighting
system components to the electrical system of the
vehicle. These hard wired circuits are integral to sev-
eral 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 exterior lighting
system components through the use of a combination
of soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
OPERATION
Following are paragraphs that briefly describe the
operation of each of the major exterior lighting sys-
tems. The hard wired circuits and components of the
exterior lighting systems may be diagnosed and
tested using conventional diagnostic tools and proce-
dures. However, conventional diagnostic methods
may not prove conclusive in the diagnosis of the Body
Control Module (BCM), the ElectroMechanical
Instrument Cluster (EMIC), the Powertrain Control
Module (PCM), or the Programmable Communica-
tions Interface (PCI) data bus network. The most
reliable, efficient, and accurate means to diagnose
the BCM, the EMIC, the PCM, and the PCI data busnetwork inputs and outputs related to the various
exterior lighting systems requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
BACKUP LAMPS
The backup (or reverse) lamps have a path to
ground at all times through their connection to the
rear lighting wire harness from a take out of the rear
body wire harness with an eyelet terminal connector
that is secured by a ground screw to the base of the
right D-pillar behind the quarter trim panel. The
backup lamps receive battery current from a fused
ignition switch output (run) fuse in the Junction
Block (JB) on the back-up lamp feed circuit only
when the backup lamp switch (manual transmission),
or backup lamp switch circuit of the Transmission
Range Sensor (TRS - electronic automatic transmis-
sion) is closed by the gearshift mechanism within the
transmission.
BRAKE LAMPS
The brake (or stop) lamps have a path to ground at
all times through their connection to the rear light-
ing wire harness from a take out of the rear body
wire harness with an eyelet terminal connector that
is secured by a screw to the base of the right D-pillar
behind the quarter trim panel. The Center High
Mounted Stop Lamp (CHMSL) has a path to ground
at all times through its connection to the rear body
wire harness from a take out of the rear body wire
harness with an eyelet terminal connector that is
secured by a ground screw to the driver side D-pillar
(left side D-pillar for left-hand drive, right side D-pil-
lar for right-hand drive) behind the quarter trim
panel. The brake lamps and CHMSL receive battery
current from a fused B(+) fuse in the Junction Block
(JB) on the brake lamp switch output circuit only
when the brake lamp switch circuit of the brake
lamp switch is closed by the brake pedal arm.
DAYTIME RUNNING LAMPS
Vehicles manufactured for sale in Canada illumi-
nate the high beam filament at a reduced intensity
when the engine is running and the exterior lamps
are turned off. This feature is enabled by the Body
Control Module (BCM) and a solid state Daytime
Running Lamps (DRL) relay, which is installed in the
Junction Block (JB) and the high beam relay is omit-
ted. When the BCM monitors an engine speed signal
of greater than 450 RPM and the status of the exte-
rior lighting switch input from the multi-function
switch is Off, the BCM duty cycles the DRL relay to
produce illumination of the headlamp high beam fil-
aments at a reduced intensity. The BCM also pro-
vides normal headlamp high beam operation through
the DRL relay on vehicles so equipped. When the
KJLAMPS/LIGHTING - EXTERIOR 8L - 5
LAMPS/LIGHTING - EXTERIOR (Continued)

BRAKE LAMP SWITCH
DESCRIPTION
The brake lamp switch is a three circuit, spring-
loaded plunger actuated switch that is secured to the
steering column support bracket under the driver
side of the instrument panel (Fig. 3). The brake lamp
switch is contained within a rectangular molded plas-
tic housing with an integral connector receptacle fea-
turing six terminal pins and a red plastic Connector
Position Assurance (CPA) lock. The switch is con-
nected to the vehicle electrical system through a ded-
icated take out and connector of the instrument
panel wire harness. The switch plunger extends
through a mounting collar on one end of the switch
housing. The plunger has a one time telescoping self-
adjustment feature that is achieved after the switch
is installed by moving an adjustment release lever on
the opposite end of the switch housing clockwise,
until it locks in a position that is parallel to the con-
nector receptacle. The brake lamp switch self-adjust-
ment is a one time feature. Once the feature has
been used, the switch cannot be readjusted. A ªDO
NOT RE-INSTALLº warning is molded into the
switch housing below the connector receptacle.
An installed brake lamp switch cannot be read-
justed or repaired. If the switch is damaged, faulty,
or removed from its mounting position for any rea-
son, it must be replaced with a new unit.
OPERATION
The brake lamp switch controls three different cir-
cuits, one normally open and two normally closed.
These circuits are described as follows:
²Brake Lamp Switch Circuit- A normally
open brake lamp switch circuit receives battery cur-
rent on a fused B(+) circuit from a fuse in the Junc-
tion Block (JB), and supplies battery current to the
brake lamps and the Controller Antilock Brake
(CAB) on a brake lamp switch output circuit when
the brake pedal is depressed (brake lamp switch
plunger released).
²Brake Lamp Switch Signal Circuit- A nor-
mally closed brake lamp switch signal circuit receives
a path to ground through a splice block located in the
instrument panel wire harness with an eyelet termi-
nal connector that is secured by a nut to a ground
stud on the driver side instrument panel end bracket
near the Junction Block (JB). This circuit supplies a
ground input to the Powertrain Control Module
(PCM) on a brake lamp switch sense circuit when the
brake pedal is released (brake lamp switch plunger is
depressed).
²Speed Control Circuit- A normally closed
speed control circuit receives battery current from
the Powertrain Control Module on a speed control
supply circuit, and supplies battery current to the
speed control servo solenoids (dump, vacuum, and
vent) on a speed control brake switch output circuit
when the speed control system is turned on and the
brake pedal is released (brake lamp switch plunger is
depressed).
Concealed within the brake lamp switch housing
the components of the self-adjusting brake switch
plunger consist of a two-piece telescoping plunger, a
split plunger locking collar, and a release wedge. The
release lever has an integral shaft with a wedge that
spreads the plunger locking collar to an open or
released position. After the switch is installed and
the brake pedal is released, the plunger telescopes to
the correct adjustment position. When the release
lever is moved to the release position, the wedge is
disengaged from the locking collar causing the collar
to apply a clamping pressure to the two plunger
halves fixing the plunger length.
The brake lamp switch can be diagnosed using con-
ventional diagnostic tools and methods.
Fig. 3 Brake Lamp Switch
1 - CONNECTOR RECEPTACLE
2 - BRAKE LAMP SWITCH
3 - PLUNGER
4 - COLLAR
5 - LEVER
8L - 16 LAMPS/LIGHTING - EXTERIORKJ

trol stalk provide detent switching for a parade mode
that maximizes the illumination intensity of all
instrument panel lighting for visibility when driving
in daylight with the exterior lamps turned on.
²Park Lamps- The internal circuitry and hard-
ware of the multi-function switch left (lighting) con-
trol stalk provide detent switching for the park
lamps.
²Rear Fog Lamps- For vehicles so equipped,
the internal circuitry and hardware of the multi-
function switch left (lighting) control stalk provide
detent switching for the optional rear fog lamps.
Rear fog lamps are optional only for vehicles manu-
factured for certain markets, where they are
required.
²Turn Signal Control- The internal circuitry
and hardware of the multi-function switch left (light-
ing) control stalk provide both momentary non-detent
switching and detent switching with automatic can-
cellation for both the left and right turn signal
lamps.
RIGHT CONTROL STALK The right (wiper) con-
trol stalk of the multi-function switch supports the
following functions and features:
²Continuous Front Wipe Modes- The internal
circuitry and hardware of the multi-function switch
right (wiper) control stalk provide two continuous
front wipe switch positions, low speed or high speed.
²Continuous Rear Wipe Mode- The internal
circuitry and hardware of the multi-function switch
right (wiper) control stalk provide one continuous
rear wipe switch position.
²Front Washer Mode- The internal circuitry
and hardware of the multi-function switch right
(wiper) control stalk switch provide front washer sys-
tem operation.
²Front Wipe-After-Wash Mode- The internal
circuitry and hardware of the multi-function switch
right (wiper) control stalk provide a wipe-after-wash
mode.
²Front Wiper Mist Mode- The internal cir-
cuitry and hardware of the multi-function switch
right (wiper) control stalk provide a front wiper sys-
tem mist mode.
²Intermittent Front Wipe Mode- The internal
circuitry and hardware of the multi-function switch
right (wiper) control stalk provide an intermittent
front wipe mode with five delay interval positions.
²Intermittent Rear Wipe Mode- The internal
circuitry and hardware of the multi-function switch
right (wiper) control stalk provide one fixed interval
intermittent rear wipe mode switch position.
²Rear Washer Mode- The internal circuitry and
hardware of the multi-function switch right (wiper)
control stalk provide rear washer system operation.OPERATION
The multi-function switch uses a combination of
resistor multiplexed and conventionally switched out-
puts to control the many functions and features it
provides. The switch receives battery current on a
fused ignition switch output (run-acc) circuit from a
fuse in the Junction Block (JB) whenever the ignition
switch is in the On or Accessory positions. The switch
receives a path to ground at all times through a
splice block located in the instrument panel wire har-
ness with an eyelet terminal connector that is
secured by a nut to a ground stud on the driver side
instrument panel end bracket near the Junction
Block (JB). Following are descriptions of how each of
the two multi-function switch control stalks operate
to control the functions and features they provide.
LEFT CONTROL STALK The left (lighting) control
stalk of the multi-function switch operates as follows:
²Front Fog Lamps- For vehicles so equipped,
the control knob on the end of the multi-function
switch left (lighting) control stalk is pulled outward
to activate the optional front fog lamps. The control
knob is mechanically keyed so that it cannot be
pulled outward unless it is first rotated to turn on
the exterior lighting. The multi-function switch pro-
vides a resistor multiplexed output to the Body Con-
trol Module (BCM) on a fog lamp switch sense
circuit, and the BCM responds by energizing or de-
energizing the front fog lamp relay in the Junction
Block (JB) as required.
²Headlamps- The control knob on the end of
the multi-function switch left (lighting) control stalk
is rotated forward (counterclockwise) to its second
detent position to activate the headlamps. The multi-
function switch provides a resistor multiplexed out-
put to the Body Control Module (BCM) on a
headlamp switch sense circuit, and the BCM
responds by energizing or de-energizing the selected
low or high beam relay (Daytime Running Lamp
relay in Canadian vehicles) in the Junction Block
(JB) as required.
²Headlamp Beam Selection- The left (lighting)
control stalk of the multi-function switch is pulled
towards the steering wheel past a detent to actuate
the integral beam select switch circuitry. Each time
the control stalk is activated in this manner, the
opposite headlamp beam from what is currently
selected will be energized. The multi-function switch
provides a ground output to the Body Control Module
(BCM) on a high beam switch sense circuit, and the
BCM responds by energizing or de-energizing the
selected low or high beam relay (Daytime Running
Lamp relay in Canadian vehicles) in the Junction
Block (JB) as required.
²Headlamp Optical Horn- The left (lighting)
control stalk of the multi-function switch is pulled
8L - 48 LAMPS/LIGHTING - EXTERIORKJ
MULTI-FUNCTION SWITCH (Continued)