2002 JEEP LIBERTY ESP

for the courtesy lamp from the connector receptacle
on the back of the lamp unit housing.
(4) Remove the courtesy lamp unit from under the
instrument panel.
INSTALLATION
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.
(1) Position the courtesy lamp unit under the
instrument panel.
(2) Reconnect the instrument panel wire harness
connector for the courtesy lamp to the connector
receptacle on the back of the lamp unit housing.
(3) Position the courtesy lamp unit to the lower
instrument panel (Fig. 10).
(4) Install and tighten the screw that secures the
integral mounting tab of the courtesy lamp unit to
the lower instrument panel.
(5) Reconnect the battery negative cable.
DOOR AJAR SWITCH
DESCRIPTION
This vehicle has four door ajar switches, one for
each door. Each switch is concealed within and inte-
gral to its respective door latch unit. The switches
are momentary leaf contact-type units that are actu-
ated by the door latch mechanisms. A short pigtail
wire and connector on each door latch connects the
door ajar switch to the vehicle electrical system
through its respective door wire harness. The door
ajar switches cannot be adjusted or repaired and, if
faulty or damaged, the door latch unit must be
replaced. (Refer to 23 - BODY/DOOR - FRONT/
LATCH - REMOVAL) or (Refer to 23 - BODY/DOOR -
REAR/LATCH - REMOVAL).
OPERATION
The door ajar switches are actuated by the door
latch mechanisms. When a door is closed and prop-
erly latched, its door ajar switch is an open circuit.
When a door is open or only partially latched, the
door ajar switch is a closed circuit. The door ajar
switches are hard wired between a body ground and
the Body Control Module (BCM). The driver side
front door ajar switch is connected to the BCM
through a driver door ajar switch sense circuit, while
the remaining three door ajar switches are connected
to the BCM through a passenger door ajar switch
sense circuit in a parallel-series arrangement. The
BCM reads the door ajar switch status through an
internal pull-up, then uses these inputs to control
many electronic functions and features of the vehicle.
The door ajar switches can be diagnosed using con-
ventional diagnostic tools and methods; however, for
proper diagnosis of the BCM, and both the hard
wired and electronic BCM outputs affected by the
door ajar switch inputs, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
FLIP-UP GLASS AJAR SWITCH
DESCRIPTION
A flip-up glass ajar switch is standard equipment
in this vehicle. This switch is concealed within and
integral to the flip-up glass latch unit. The switch is
a momentary leaf contact-type unit that is actuated
by the flip-up glass latch mechanism. A dedicated
connector receptacle on the flip-up glass latch unit
connects the flip-up glass ajar switch to the vehicle
electrical system through the tailgate wire harness.
The flip-up glass ajar switch cannot be adjusted or
repaired and, if faulty or damaged, the flip-up glass
latch unit must be replaced. (Refer to 23 - BODY/
SWING GATE/FLIP-UP GLASS LATCH - REMOV-
AL).
OPERATION
The flip-up glass ajar switch is actuated by the
flip-up glass latch mechanism. When the flip-up glass
is closed and properly latched, the flip-up glass ajar
switch is an open circuit. When the flip-up glass is
open or only partially latched, the flip-up glass ajar
switch is a closed circuit. The flip-up glass ajar
switch is hard wired between a body ground, the
Body Control Module (BCM), and the rear wiper
motor. The output of the switch is connected to the
BCM and rear wiper motor through a flip-up glass
ajar switch sense circuit. The BCM reads the flip-up
glass ajar switch status through an internal pull-up,
then uses this input to control many electronic func-
KJLAMPS/LIGHTING - INTERIOR 8L - 77
COURTESY LAMP UNIT (Continued)

FRONT FOG LAMPS
Vehicles equipped with optional front fog lamps
have a premium Body Control Module (BCM), a front
fog lamp relay installed in the Junction Block (JB),
and a front fog lamp switch integral to the left (light-
ing) control stalk of the multi-function switch. The
front fog lamps have a path to ground at all times
through their connection to the front fascia wire har-
ness from two take outs of the headlamp and dash
wire harness with eyelet terminal connectors that
are secured by ground screws to the left inner fender
shield in the engine compartment. The BCM controls
front fog lamp operation by monitoring the exterior
lighting switch input from the multi-function switch,
then energizing or de-energizing the front fog lamp
relay control coil; and, by sending the appropriate
electronic message to the instrument cluster over the
Programmable Communications Interface (PCI) data
bus to turn the front fog lamp indicator on or off.
When the front fog lamp relay is energized, it pro-
vides battery current from a fused B(+) fuse in the
JB to the front fog lamps through the front fog lamp
relay output circuit. The BCM provides a battery
saver (load shedding) feature for the front fog lamps,
which will turn these lamps off if they are left on for
more than about eight minutes with the ignition
switch in the Off position. In certain markets where
required, the front fog lamps are also turned off by
the BCM whenever the headlamp high beams are
selected. Each front fog lamp includes an integral
adjustment screw to be used for static aiming the fog
lamp beams.
HAZARD WARNING LAMPS
With the hazard switch in the On position, the
hazard warning system is activated causing the haz-
ard switch button illumination lamp, the right and
left turn signal indicators, and the right and left turn
signal lamps to flash on and off. When the hazard
warning system is activated, the circuitry within the
hazard switch and electronic combination flasher
unit will repeatedly energize and de-energize two
internal relays that switch battery current from a
fused B(+) fuse in the Junction Block (JB) to the
right side and left side turn signal indicators, and
turn signal lamps through the right and left turn sig-
nal circuits. The flashing of the hazard switch button
illumination lamp is performed internally by the haz-
ard switch and combination flasher unit circuit
board. The hazard warning lamps can also be ener-
gized by the Body Control Module (BCM) through a
hazard lamp control circuit input to the hazard
switch and combination flasher unit.HEADLAMPS
The headlamp system includes the Body Control
Module (BCM), a low beam relay installed in the
Junction Block (JB), a high beam relay installed in
the JB (except Canada), a solid state Daytime Run-
ning Lamps (DRL) relay installed in the JB (Canada
only), and the exterior lighting (headlamp and dim-
mer) switches integral to the left (lighting) control
stalk of the multi-function switch. The headlamp
bulbs have a path to ground at all times through
their connection to the grille opening reinforcement
wire harness from two take outs of the headlamp and
dash wire harness with eyelet terminal connectors
that are secured by ground screws to the left inner
fender shield in the engine compartment. The BCM
controls the headlamp operation by monitoring the
exterior lighting switch inputs from the multi-func-
tion switch, then energizing or de-energizing the con-
trol coils of the low beam relay, the high beam relay,
or the solid state circuitry of the DRL relay; and, by
sending the appropriate electronic message to the
instrument cluster over the Programmable Commu-
nications Interface (PCI) data bus to turn the high
beam indicator on or off. When each respective relay
is energized, it provides battery current from a fused
B(+) fuse in the Power Distribution Center (PDC)
through a relay (low beam, high beam, or DRL) out-
put circuit and four separate fuses in the JB through
individual fused right and left, low and high beam
output circuits to the appropriate headlamp bulb fil-
aments. The BCM provides a battery saver (load
shedding) feature for the headlamps, which will turn
these lamps off if they are left on for more than
about eight minutes with the ignition switch in the
Off position; and, a headlamp delay feature with a
DRBIIItscan tool programmable delay interval.
Each headlamp includes an integral adjustment
screw to be used for static aiming of the headlamp
beams.
HEADLAMP LEVELING
In certain markets where required, a headlamp
leveling system is provided on the vehicle. The head-
lamp leveling system includes unique headlamp units
equipped with a headlamp leveling actuator motor,
and a rotary thumbwheel actuated headlamp leveling
switch on the instrument panel. The headlamp level-
ing system allows the headlamp beams to be
adjusted to one of four vertical positions to compen-
sate for changes in inclination caused by the loading
of the vehicle suspension. The actuator motors are
mechanically connected through an integral pushrod
to an adjustable headlamp reflector. The headlamp
leveling switch is a resistor multiplexed unit that
provides one of four voltage outputs to the headlamp
leveling motors. The headlamp leveling motors will
8Ls - 6 LAMPSKJ
LAMPS/LIGHTING - EXTERIOR (Continued)

switch module housing is the hazard switch circuitry
and an electronic circuit board with the integral com-
bination flasher circuitry. The electronic combination
flasher circuitry performs both the hazard flasher
and turn signal flasher functions.
The hazard switch module cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The hazard switch button is slightly recessed in
the instrument panel when the switch is in the Off
position, and latches at a position that is flush with
the outer surface of the instrument panel when in
the On position. The hazard switch module produces
an audible clicking sound that emulates the sound of
a conventional flasher whenever the turn signals or
the hazard warning system are activated. The hazard
switch module receives battery current on a fused
B(+) circuit from a fuse in the Junction Block (JB) at
all times for operation of the hazard warning, and on
a fused ignition switch output (run) circuit from
another fuse in the JB whenever the ignition switch
is in the On position for operation of the turn signals.
The module receives a path to ground 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 JB. Inputs to
and outputs from the hazard switch module include:
²Panel Lamps Dimmer Input- A non-service-
able incandescent bulb soldered onto the hazard
switch module circuit board provides illumination of
the switch button when the exterior lighting is
turned On through an input received on the fusedpanel lamps dimmer switch signal circuit. However,
this bulb flashes on and off at full intensity whenever
the hazard switch button is in the On position,
regardless of the status of the exterior lighting.
²Hazard Switch Input- The combination
flasher circuitry of the hazard switch module receives
an internal ground input from the hazard switch to
request hazard flasher operation.
²Multi-Function Switch Input- The combina-
tion flasher circuitry of the hazard switch module
receives separate ground inputs from the turn signal
switch circuitry of the multi-function switch on right
and left turn switch sense circuits to request right or
left turn signal flasher operation.
²Body Control Module Input- The Body Con-
trol Module (BCM) can request hazard flasher opera-
tion by providing a ground path to the combination
flasher circuitry of the hazard switch module through
a hazard lamp control circuit.
²Turn Signal Output- The combination flasher
circuitry within the hazard switch module responds
to the flasher request inputs by energizing and
de-energizing two miniature relays on the module
circuit board. These relays control the switch output
through the right and left turn signal circuits. One
relay controls the right lamps, while the other con-
trols the left.
Because of active electronic elements within the
hazard switch module, it cannot be tested with con-
ventional automotive electrical test equipment. If the
hazard switch module is believed to be faulty, replace
the switch with a known good unit to confirm system
operation.
REMOVAL
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.
(1) Disconnect and isolate the battery negative
cable.
Fig. 21 Hazard Switch
1 - HAZARD SWITCH BUTTON
2 - SCREW (1)
3 - MOUNTING BRACKET TABS
KJLAMPS8Ls-29
HAZARD SWITCH (Continued)

²Parade Mode- The internal circuitry and hard-
ware of the multi-function switch left (lighting) con-
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 output 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.
8Ls - 48 LAMPSKJ
MULTI-FUNCTION SWITCH (Continued)

²Headlamp Optical Horn- The left (lighting)
control stalk of the multi-function switch is pulled
towards the steering wheel to just before a detent, to
momentarily activate the headlamp optical horn fea-
ture. The high beams will remain illuminated until
the control stalk is released. The multi-function
switch provides a ground output on a high beam
relay control circuit to energize the headlamp high
beam relay (Daytime Running Lamp relay in Cana-
dian vehicles) in the Junction Block (JB) as required.
²Interior Lamps Defeat- The control ring on
the multi-function switch left (lighting) control stalk
is rotated to a full rearward (clockwise) detent to
defeat the illumination of all interior courtesy lamps.
The multi-function switch provides a resistor multi-
plexed output to the Body Control Module (BCM) on
a panel lamps dimmer switch mux circuit, and the
BCM responds by de-energizing its internal courtesy
lamp driver circuit.
²Interior Lamps On- The control ring on the
multi-function switch left (lighting) control stalk is
rotated to a full forward (counterclockwise) detent to
illuminate all interior courtesy lamps. The multi-
function switch provides a resistor multiplexed out-
put to the Body Control Module (BCM) on a panel
lamps dimmer switch mux circuit, and the BCM
responds by energizing its internal courtesy lamp
driver circuit.
²Panel Lamps Dimming- The control ring on
the multi-function switch left (lighting) control stalk
is rotated to one of six minor intermediate detents to
simultaneously select the desired illumination inten-
sity of all adjustable instrument panel and instru-
ment cluster lighting. The control ring is rotated
rearward (clockwise) to dim, or forward (counter-
clockwise) to brighten. The multi-function switch pro-
vides a resistor multiplexed output to the Body
Control Module (BCM) on a panel lamps dimmer
switch mux circuit, and the BCM responds by send-
ing an electronic panel lamps dimming level message
to the ElectroMechanical Instrument Cluster (EMIC)
over the Programmable Communications Interface
(PCI) data bus. The EMIC electronic circuitry then
provides the proper PWM output to the cluster illu-
mination lamps and the VFD on the EMIC circuit
board, then provides a matching PWM output on the
hard wired fused panel lamps dimmer switch signal
circuit.
²Parade Mode- The control ring on the multi-
function switch left (lighting) control stalk is rotated
to an intermediate detent that is one detent rear-
ward (clockwise) from the full forward (counterclock-
wise) detent to select the Parade mode. The multi-
function switch provides a resistor multiplexed
output to the Body Control Module (BCM) on a panel
lamps dimmer switch mux circuit, and the BCMresponds by sending an electronic panel lamps dim-
ming level message to the ElectroMechanical Instru-
ment Cluster (EMIC) over the Programmable
Communications Interface (PCI) data bus. The EMIC
electronic circuitry then provides the proper PWM
output to the cluster illumination lamps and the
VFD on the EMIC circuit board, then provides a
matching PWM output on the hard wired fused panel
lamps dimmer switch signal circuit to illuminate all
lamps at full (daylight) intensity with the exterior
lamps turned On.
²Park Lamps- The control knob on the end of
the multi-function switch left (lighting) control stalk
is rotated forward (counterclockwise) to its first
detent from the Off position to activate the park
lamps. The multi-function switch provides a resistor
multiplexed output to the Body Control Module
(BCM) on a headlamp switch sense circuit, and the
BCM responds by energizing or de-energizing the
park lamp relay in the Junction Block (JB) as
required.
²Rear Fog Lamps- For vehicles so equipped,
the control knob on the end of the multi-function
switch left (lighting) control stalk is rotated forward
(counterclockwise) to its third detent position to acti-
vate the rear fog lamps. The multi-function switch
provides a resistor multiplexed output to the Body
Control Module (BCM) on a headlamp switch sense
circuit, and the BCM responds by energizing or de-
energizing the rear fog lamp relay in the Junction
Block (JB) as required. Rear fog lamps are optional
only for vehicles manufactured for certain markets,
where they are required.
²Turn Signal Control- The left (lighting) con-
trol stalk of the multi-function switch is moved
upward to activate the right turn signal circuitry,
and, downward to activate the left turn signal cir-
cuitry. The turn signal switch has a detent position
in each direction that provides turn signals with
automatic cancellation, and an intermediate, momen-
tary position in each direction that provides turn sig-
nals only until the left multi-function switch control
stalk is released. When the control stalk is moved to
a turn signal switch detent position, the cancel
actuator extends toward the center of the steering
column. A turn signal cancel cam that is integral to
the clockspring rotates with the steering wheel and
the cam lobes contact the cancel actuator when it is
extended from the left multi-function switch. When
the steering wheel is rotated during a turning
maneuver, one of the two turn signal cancel cam
lobes will contact the turn signal cancel actuator. The
cancel actuator latches against the cancel cam rota-
tion in the direction opposite that which is signaled.
In other words, if the left turn signal detent is
selected, the lobes of the cancel cam will ratchet past
KJLAMPS8Ls-49
MULTI-FUNCTION SWITCH (Continued)

the cancel actuator when the steering wheel is
rotated to the left, but will unlatch the cancel actua-
tor as the steering wheel rotates to the right and
returns to center, which will cancel the turn signal
event and release the control stalk from the detent so
it returns to the neutral Off position. When a turn
signal is activated, the multi-function switch provides
a ground output on a right or left turn switch sense
circuit to the combination flasher circuitry within the
hazard switch, and the combination flasher flashes
the turn signal lamps.
RIGHT CONTROL STALK The right (wiper) con-
trol stalk of the multi-function switch operates as fol-
lows:
²Continuous Front Wipe Modes- The control
knob on the end of the multi-function switch right
(wiper) control stalk is rotated to an intermediate
detent that is one detent rearward (counterclockwise)
from the full forward (clockwise) detent to select the
low speed continuous front wiper mode, or to its full
forward (clockwise) detent to select the high speed
continuous front wiper mode. The multi-function
switch provides a resistor multiplexed output to the
Body Control Module (BCM) on a front wiper switch
mux circuit, and the BCM responds by energizing the
wiper on/off relay in the Power Distribution Center
(PDC) for the front low speed continuous wipe mode,
or the wiper on/off relay and the wiper high/low relay
in the PDC for the front high speed continuous wipe
mode as required.
²Continuous Rear Wipe Mode- The control
ring on the multi-function switch right (wiper) con-
trol stalk is rotated to the most forward (clockwise)
detent to select the continuous rear wiper mode. The
multi-function switch provides a battery current out-
put to the rear wiper motor on a rear wiper on driver
circuit to signal the rear wiper motor to operate in
the continuous wipe mode.
²Front Washer Mode- The right (wiper) control
stalk of the multi-function switch is pulled towards
the steering wheel to momentarily activate the
washer pump in the front washer mode. The washer
pump will continue to operate in the front washer
mode until the control stalk is released. The multi-
function switch provides a ground output on a
washer pump sense circuit, and battery current on a
washer pump driver circuit to energize the washer
pump in the front washer mode.
²Front Wiper Mist Mode- The right (wiper)
control stalk of the multi-function switch is pushed
towards the floor to momentarily activate the front
wiper motor in the mist mode. The front wiper motor
will continue to operate in the mist mode until the
control stalk is released. The multi-function switch
provides a resistor multiplexed output to the Body
Control Module (BCM) on a front wiper switch muxcircuit, and the BCM responds by energizing the
wiper on/off relay in the Power Distribution Center
(PDC) to operate the front wiper motor momentarily
at low speed to provide the front wiper mist mode.
²Intermittent Front Wipe Mode- The control
knob on the end of the multi-function switch right
(wiper) control stalk is rotated to one of five minor
intermediate detents to select the desired intermit-
tent front wipe delay interval. The control knob is
rotated rearward (counterclockwise) to increase the
delay, or forward (clockwise) to decrease the delay.
The multi-function switch provides a resistor multi-
plexed output to the Body Control Module (BCM) on
a front wiper switch mux circuit, and the BCM
responds by energizing the wiper on/off relay in the
Power Distribution Center (PDC) to operate the front
wiper motor at the selected delay intervals.
²Intermittent Rear Wipe Mode- The control
ring on the multi-function switch right (wiper) con-
trol stalk is rotated to the center detent to select the
intermittent rear wiper mode. The multi-function
switch provides a battery current output to the rear
wiper motor on a rear wiper intermittent driver cir-
cuit to signal the rear wiper motor to operate in the
intermittent wipe mode.
²Rear Washer Mode- The control ring on the
multi-function switch right (wiper) control stalk is
rotated to either the full forward (clockwise) or full
rearward (counterclockwise) momentary positions to
activate the washer pump in the rear washer mode.
The washer pump will continue to operate in the rear
washer mode until the control ring is released. The
multi-function switch provides a ground output on a
washer pump driver circuit, and battery current on a
washer pump sense circuit to energize the washer
pump in the rear washer mode.
DIAGNOSIS AND TESTING - MULTI-FUNCTION
SWITCH
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
8Ls - 50 LAMPSKJ
MULTI-FUNCTION SWITCH (Continued)

The CMTC may also be integrated with the Uni-
versal Transmitter. If so, your CMTC module will
have three buttons centered together between the
outer four buttons. Below the three buttons are cor-
responding dots to indicate which button you are
using.
The Compass Mini-Trip Computer includes the fol-
lowing display options:
²Compass and thermometer- provides the out-
side temperature and one of eight compass readings
to indicate the direction the vehicle is facing.
²Average fuel economy- shows the average
fuel economy since the last trip computer reset.
²Distance to empty- shows the estimated dis-
tance that can be travelled with the fuel remaining
in the fuel tank. This estimated distance is computed
using the average miles-per-gallon from the last 30
gallons of fuel used.
²Instant fuel economy- shows the present fuel
economy based upon the current vehicle distance and
fuel used information.
²Trip odometer- shows the distance travelled
since the last trip computer reset.
²Elapsed time- shows the accumulated igni-
tion-on time since the last trip computer reset.
²Blank screen- the CMTC compass/thermome-
ter/trip computer VFD is turned off.
If the vehicle is equipped with the optional Univer-
sal Transmitter transceiver, the CMTC will also dis-
play messages and an icon indicating when the
Universal Transmitter is being trained, which of the
three transmitter buttons is transmitting, and when
the transceiver is cleared.
Data input for all CMTC functions, including VFD
dimming level, is received through PCI data bus
messages. The CMTC module uses its internal pro-
gramming and all of its data inputs to calculate and
display the requested data. If the data displayed is
incorrect, perform the self-diagnostic tests as
described in this group. If these tests prove inconclu-
sive, the use of a DRBIIItscan tool and the proper
Diagnostic Procedures manual are recommended for
further testing of the CMTC module and the PCI
data bus.
The CMTC module cannot be repaired, and is
available for service only as a unit. This unit
includes the push button switches and the plastic
module and display lens. If any of these components
is faulty or damaged, the complete CMTC module
must be replaced. The incandescent bulbs used for
CMTC push button back-lighting are available for
service replacement.
DESCRIPTION - COMPASS
While in the compass/thermometer mode, the com-
pass will display the direction in which the vehicle ispointed using the eight major compass headings
(Examples: north is N, northeast is NE). The self-cal-
ibrating compass unit requires no adjusting in nor-
mal use. The only calibration that may prove
necessary is to drive the vehicle in three complete
circles at 5 to 8 kilometers-per-hour (3 to 5 miles-per-
hour), on level ground, in not less than forty-eight
seconds. This will reorient the compass unit to its
vehicle.
The compass unit also will compensate for magne-
tism the body of the vehicle may acquire during nor-
mal use. However, avoid placing anything magnetic
directly on the roof of the vehicle. Magnetic mounts
for an antenna, a repair order hat, or a funeral pro-
cession flag can exceed the compensating ability of
the compass unit if placed on the roof panel. Mag-
netic bit drivers used on the fasteners that hold the
overhead console assembly to the roof header can
also affect compass operation. If the vehicle roof
should become magnetized, the demagnetizing and
calibration procedures found in this group may be
required to restore proper compass operation.
DESCRIPTION - THERMOMETER
The thermometer displays the outside ambient
temperature in whole degrees. The temperature dis-
play can be toggled from Fahrenheit to Celsius by
using the U.S./Metric button. The displayed temper-
ature is not an instant reading of conditions, but an
average temperature. It may take the thermometer
display several minutes to respond to a major tem-
perature change, such as driving out of a heated
garage into winter temperatures.
When the ignition switch is turned to the Off posi-
tion, the last displayed temperature reading stays in
the Body Control Module (BCM) unit memory. When
the ignition switch is turned to the On position
again, the CMTC will display the memory tempera-
ture for one minute; then update the display to the
current average temperature reading within five
minutes.
The thermometer function is supported by an
ambient temperature sensor. The sensor is mounted
outside the passenger compartment near the front
and center of the vehicle, and is hard wired to the
Body Control Module (BCM). The BCM sends tem-
perature status messages to the CMTC module over
the PCI data bus network. The ambient temperature
sensor is available as a separate service item, refer to
additional information later in this section.
OPERATION
The compass mini-trip computer operates when the
ignition is in the ON position. The VFD will display
the last display before ignition was turned OFF. The
four outer buttons operate:
KJMESSAGE SYSTEMS 8M - 5
COMPASS/MINI-TRIP COMPUTER (Continued)

NOTE: Individual channels cannot be erased. Eras-
ing the transmitter codes will erase ALL pro-
grammed codes.
STANDARD PROCEDURE - SETTING
TRANSMITTER CODES
(1) Turn off the engine.
(2) Erase the factory test codes by pressing but-
tons 1 and 3. Release the buttons when the two
green lights begin to flash (about 20 seconds).
(3) Choose one of the three buttons to train. Place
the hand-held transmitter within one inch of the uni-
versal transmitter and push the buttons on both
transmitters. The green dot below the house symbol
will begin to flash slowly.
(4) When the red light on the universal transmit-
ter begins to flash rapidly (this may take as long as
60 seconds), release both buttons. Your universal
transmitter is now ªtrainedº. To train the other but-
tons, repeat Step 3 and Step 4. Be sure to keep your
hand-held transmitter in case you need to retrain the
universal transmitter.
AMBIENT TEMP SENSOR
DESCRIPTION
Ambient air temperature is monitored by the Com-
pass Mini-Trip Computer (CMTC) through ambient
temperature sensor messages received from the Body
Control Module (BCM) over the Programmable Com-
munications Interface (PCI) data bus network. The
BCM receives a hard wired input from the ambient
temperature sensor. The ambient temperature sensor
(Fig. 8) is a variable resistor mounted in front the
radiator, behind the grille, near the center of the
vehicle.
Refer toBody Control Modulein Electronic Con-
trol Modules. For complete circuit diagrams, refer to
the appropriate wiring information. The ambient
temperature sensor cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The ambient temperature sensor is a variable
resistor that operates on a five-volt reference signal
sent to it by the BCM. The resistance in the sensor
changes as temperature changes, changing the tem-
perature sensor signal circuit voltage to the BCM.
Based upon the resistance in the sensor, the BCM
senses a specific voltage on the temperature sensor
signal circuit, which it is programmed to correspond
to a specific temperature. The BCM then sends the
proper ambient temperature messages to the CMTC
over the PCI data bus.
The thermometer function is supported by the
ambient temperature sensor, a wiring circuit, the
Body Control Module (BCM), the Programmable
Communications Interface (PCI) data bus, and a por-
tion of the Compass Mini-Trip Computer module.
The ambient temperature sensor circuit can also be
diagnosed by referring toDiagnosis and Testing -
Ambient Temperature Sensor, and Diagnosis
and Testing - Ambient Temperature Sensor Cir-
cuit. If the temperature sensor and circuit are con-
firmed to be OK, but the temperature display is
inoperative or incorrect, refer toDiagnosis and
Testing - Compass Mini-Trip Computerin this
section. For complete circuit diagrams, refer to the
appropriate wiring information.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire har-
ness connector.
(2) Measure the resistance of the ambient temper-
ature sensor. At ±40É C (±40É F), the sensor resis-
tance is 336 kilohms. At 55É C (140É F), the sensor
resistance is 2.488 kilohms. The sensor resistance
should read between these two values. If OK, refer to
Diagnosis and Testing - Ambient Temperature
Sensor Circuitin this group. If not OK, replace the
faulty ambient temperature sensor.
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR CIRCUIT
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire har-
ness connector and the Body Control Module wire
harness connector.
(2) Connect a jumper wire between the two termi-
nals in the body half of the ambient temperature sen-
sor wire harness connector.
Fig. 8 Ambient Temperature Sensor
KJMESSAGE SYSTEMS 8M - 9
UNIVERSAL TRANSMITTER (Continued)