2003 JEEP GRAND CHEROKEE left turn signal

LEFT (LIGHTING) MULTI-FUNCTION SWITCH
TURN SIGNAL AND HAZARD WARNING SWITCH TESTS
SWITCH POSITION CONTINUITY
BETWEEN
TURN HAZARD
Neutral Off No Related Continuity
Left Off Pins2&8
Right Off Pins2&7
Neutral On Pins2&9
EXTERIOR LIGHTING SWITCH TESTS
SWITCH POSITION CONTINUITY
BETWEENRESISTANCE
BETWEENRESISTANCE RANGE (OHMS)
Off - Pins4&113743 - 3824
Park Lamps On - Pins4&11 901-926
Head Lamps On - Pins4&11 345-358
Auto Headlamps On - Pins4&11 74-81
Fog Lamps Pins1&2 - -
Optical Horn Pins2&5 - -
High Beam Pins2&6 - -
INTERIOR LIGHTING SWITCH TESTS
Dome Lamp Disable
On- Pins4&9 63-70
Panel Lamps
Dimming Position 1- Pins4&9 198-208
Dimming Position 2 - Pins4&9 551-569
Dimming Position 3 - Pins4&9 905-929
Dimming Position 4 - Pins4&91258 - 1290
Dimming Position 5 - Pins4&9 1611-1651
Dimming Position 6 - Pins4&91965 - 2011
Parade Mode On - Pins4&93534 - 3611
Dome Lamp Enable
On- Pins4&9 7811-7974
Fig. 23 Left Multi -Function Switch Test
WJLAMPS/LIGHTING - EXTERIOR 8L - 21
LEFT MULTI-FUNCTION SWITCH (Continued)

(4) Position the lower tilting steering column
shroud to the underside of the steering column (Fig.
29).
(5) Install and tighten the screw that secures the
lower steering column shroud housing. Tighten the
screw to 1.9 N´m (17 in. lbs.).
(6) Align the upper tilting steering column shroud
to the lower shroud and snap the two shroud halves
together.
(7) Reconnect the battery negative cable.
INSTALLATION - MULTI-FUNCTION SWITCH
MOUNTING HOUSING
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
NOTE: Before starting this procedure, be certain
that the front wheels are still in the straight-ahead
position.
(1) Rotate the turn signal cancel cam in the multi-
function switch housing until the alignment hole in
the one cam lobe is aligned with the alignment hole
in the back of the housing. The oblong hole in the
hub of the cam should now be at the top, and the
locating tab in the hub of the cam should be at the
bottom (Fig. 30).
(2) Position the multi-function switch housing onto
the top of the steering column. The locating tab in
the hub of the turn signal cancel cam must be
engaged with the alignment groove in the bottom of
the upper steering column shaft.
(3) Install and tighten the screw that secures the
multi-function switch housing to the top of the col-
umn housing (Fig. 31). Tighten the screw to 1.9 N´m
(17 in. lbs.).
(4) Reinstall the right multi-function switch onto
the multi-function switch housing. (Refer to 8 -
ELECTRICAL/WIPERS/WASHERS/RIGHT MULTI-
FUNCTION SWITCH - INSTALLATION).
(5) Reinstall the left multi-function switch onto the
multi-function switch housing. (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/LEFT
Fig. 29 Steering Column Shrouds Remove/Install
1 - UPPER TILTING COLUMN SHROUD
2 - FIXED COLUMN SHROUD
3 - LOWER TILTING COLUMN SHROUD
4 - SCREW
Fig. 30 Turn Signal Cancel Cam Alignment
1 - ALIGNMENT HOLE
2 - MULTI-FUNCTION SWITCH MOUNTING HOUSING
3 - ALIGNMENT HOLE
4 - TURN SIGNAL CANCEL CAM
5 - LOCATING TAB
6 - WASHER
7 - TURN SIGNAL SWITCH CANCEL ACTUATOR
8L - 24 LAMPS/LIGHTING - EXTERIORWJ
LEFT MULTI-FUNCTION SWITCH (Continued)

MULTI-FUNCTION SWITCH - INSTALLATION -
LEFT MULTI-FUNCTION SWITCH).
(6) Reinstall the clockspring onto the multi-func-
tion switch housing. (Refer to 8 - ELECTRICAL/RE-
STRAINTS/CLOCKSPRING - INSTALLATION).
(7) Reconnect the battery negative cable.
PARK/TURN SIGNAL LAMP
REMOVAL - BULBS
(1) Remove the headlamp module.
(2) Rotate the turn signal bulb socket 1/4 turn
counter clockwise.
(3) Remove the bulb socket from module.
(4) Remove the bulb from socket.
INSTALLATION - BULBS
(1) Press the bulb into socket.
(2) Position the bulb socket in module.
(3) Rotate the turn signal bulb socket 1/4 turn
clockwise.
(4) Install the headlamp module.
TAIL LAMP
DESCRIPTION
The taillamp module contains a housing, lens, and
three bulbs. A dual filament bulb is used for tail and
stop functions. A single filament bulb is used for turn
signal operations. A separate bulb is used for back-up
illumination.
OPERATION
All exterior lighting function are controlled by the
multifunction switch. Stop lamp functions are con-
trolled by the stoplamp switch. The back-up lamps
are controlled by the back-up lamp switch.
REMOVAL
REMOVAL - BULBS
The brake, turn signal, back-up, and side marker
lamp bulbs are incorporated into the tail lamp.
(1) Remove the tail lamp.
(2) Rotate the bulb socket counterclockwise.
(3) Separate the socket from the lamp
(4) Remove the bulb from the socket (Fig. 32).
REMOVAL - LAMP
The brake, turn signal, back-up, and side marker
lamps are incorporated in the tail lamp.
(1) Remove the screws attaching the lamp to body
(Fig. 33).
(2) Disengage the lamp from the alignment pin.
(3) Disconnect lamp wire harness connector.
(4) Separate lamp from vehicle.
Fig. 31 Multi-Function Switch Mounting Housing
Screw Remove/Install
1 - CLOCK SPRING
2 - SCREW
3 - MULTI-FUNCTION SWITCH MOUNTING HOUSING
Fig. 32 Tail Lamp Bulbs
1 - TAIL/STOP BULB
2 - TAIL LAMP
3 - BACK-UP BULB
4 - TURN SIGNAL BULB
WJLAMPS/LIGHTING - EXTERIOR 8L - 25
LEFT MULTI-FUNCTION SWITCH (Continued)

INSTALLATION
INSTALLATION - BULBS
(1) Position the bulb in socket and push into place.
(2) Position the bulb socket in the lamp and rotate
clockwise.
(3) Install the lamp.
INSTALLATION - LAMP
The brake, turn signal, back-up, and side marker
lamps are incorporated in the tail lamp.
(1) Position the lamp.
(2) Connect the lamp wire harness connector.
(3) Align the pin with the retainer and press the
lamp inward to engage.
(4) Install the screws attaching the lamp to body.
TURN SIGNAL CANCEL CAM
DESCRIPTION
The turn signal cancel cam is concealed within the
multi-function switch housing below the steering
wheel and the clockspring mechanism. The turn sig-
nal cancel cam consists of a disc unit with two inte-
gral lobes. The upper lobe of the cam has an
alignment hole that is used to align it with another
hole in the back of the multi-function switch mount-
ing housing. The upper surface of the turn signal
cancel cam features three holes, two round and one
oblong. These holes engage and key the cancel cam to
three matching pins in the hub of the clockspring
mechanism. The hub of the clockspring and the turn
signal cancel cam rotate with the steering wheel. The
centered clockspring housing is then secured to the
multi-function switch mounting housing over the top
of the turn signal cancel cam.
The turn signal cancel cam is serviced as a assem-
bly with the multi-function switch housing. The turn
signal cancel cam cannot be repaired and, if faulty or
damaged, the multi-function switch mounting hous-
ing unit must be replaced. (Refer to 8 - ELECTRI-
CAL/LAMPS/LIGHTING - EXTERIOR/LEFT MULTI-
FUNCTION SWITCH - REMOVAL - MULTI-
FUNCTION SWITCH MOUNTING HOUSING).
OPERATION
The turn signal cancel cam has two lobes. When
the turn signals are activated by moving the left
multi-function switch control stalk to a detent posi-
tion, a turn signal cancel actuator is extended from
the inside surface of the multi-function switch hous-
ing toward the center of the steering column and the
turn signal cancel cam. When the steering wheel is
rotated during a turning maneuver, one of the two
turn signal cancel cam lobes will contact the turn sig-
nal cancel actuator. The cancel actuator latches
against the cancel cam rotation in the direction oppo-
site that which is signaled.
Fig. 33 Tail Lamp
1 - CONNECTOR
2 - RETAINER
3 - TAILLAMP (STOP, TURN, BACK-UP, SIDE MARKER)
4 - PIN
8L - 26 LAMPS/LIGHTING - EXTERIORWJ
TAIL LAMP (Continued)

for door and liftgate open indications and to show if a
turn signal has been left on. The EVIC messages and
displays are coordinated with warning indicators in
the instrument cluster to avoid duplication.
The EVIC module contains a central processing
unit and interfaces with other electronic modules in
the vehicle over the Programmable Communications
Interface (PCI) data bus network. The PCI data bus
network allows the sharing of sensor information.
This helps to reduce wire harness complexity, reduce
internal controller hardware, and reduce component
sensor current loads. At the same time, this system
provides increased reliability, enhanced diagnostics,
and allows the addition of many new feature capabil-
ities.
The EVIC module includes the following display
options:
²Compass and Temperature- 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 distance- 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.
²Distance to service- shows the distance
remaining until the next scheduled service interval.
²Tire Pressure- shows the tire pressure in each
tire.
²Blank screen- the EVIC compass/temperature/
trip computer VFD is turned off.
The EVIC is capable of displaying the following
alert messages, which are accompanied by an audible
announcement consisting of a series of beeps:
²TURN SIGNALS ON (with vehicle graphic)-
Indicates that a turn signal has remained on for
about 1.6 kilometers (one mile).
²PERFORM SERVICE- Indicates that a cus-
tomer programmable service interval distance has
been reached.
²DOOR OPEN (one or more, with vehicle
graphic)- Indicates that a door is open or not fully
closed.
²LIFTGATE OPEN (with vehicle graphic)-
Indicates that the liftgate is open or not fully closed.
²LIFTGLASS OPEN (with vehicle graphic)-
Indicates that the liftglass is open or not fully closed.²COOLANT LEVEL LOW (with vehicle
graphic)- Indicates that the coolant level in the
engine coolant reservoir is low.
²XX LOW PRESSURE (with vehicle graphic)
- Indicates that the air pressure in the selected tire
is low.
²WASHER FLUID LOW (with vehicle
graphic)- Indicates that the fluid level in the
washer fluid reservoir is low.
The EVIC ªMenuº push button provides the vehicle
operator with a user interface, which allows the
selection of several optional customer programmable
electronic features to suit individual preferences.
Refer toELECTRONIC VEHICLE INFORMA-
TION CENTER PROGRAMMINGin the Service
Procedures section of this group for more information
on the customer programmable feature options.
If the vehicle is equipped with the optional mem-
ory system, the EVIC will display the following mem-
ory system messages:
²MEMORY #X POSITION SET (X = Driver 1
or Driver 2)- This message appears in the EVIC
display each time the memory system is successfully
programmed. It is accompanied by an audible
announcement chime tone.
²MEMORY SYSTEM DISABLED- The memory
system is automatically disabled while the driver
side seat belt is fastened and/or while the automatic
transmission gear selector is in any position except
Park or Neutral. This message appears in the EVIC
display as a reminder when a memory switch push
button is depressed while the memory system is dis-
abled. If the REMOTE LINKED TO MEMORY cus-
tomer programmable feature has been selected, this
message will also appear when the Unlock button of
the Remote Keyless Entry (RKE) transmitter is
depressed while the memory system is disabled.
If the vehicle is equipped with the optional Univer-
sal Transmitter transceiver, the EVIC 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.
If the vehicle is equipped with the optionalTire
Pressure Monitoring System, the EVIC will also
display messages and an icon indicating when the
tire air pressure falls below a given set-point, and
which of the five tires is transmitting the low pres-
sure warning, and when the condition is cleared.
Refer to the Tires/Wheels section of this manual for
complete Tire Pressure Monitoring System descrip-
tion. Refer to this section of the service manual for
EVIC modules function description for the Tire Pres-
sure Monitoring.
Data input for all EVIC functions, including VFD
dimming level, is received through PCI data bus
WJMESSAGE SYSTEMS 8M - 7
ELECTRONIC VEHICLE INFO CENTER (Continued)

DESCRIPTION - OUTSIDE REAR VIEW MIRROR
An automatic dimming outside rear view mirror is
an available factory-installed option for the driver
side of the vehicle, if the vehicle is also equipped
with the automatic day/night inside rear view mirror.
The automatic dimming outside mirror is completely
controlled by the circuitry of the automatic day/night
inside rear view mirror. The automatic dimming out-
side mirror will automatically change the reflectance
of the driver side outside rear view mirror to protect
the driver from the unwanted headlight glare of
trailing vehicles while driving at night. The auto-
matic dimming outside mirror will only operate when
the ignition switch is in the On position.
The automatic dimming outside mirror sensitivity
cannot be repaired or adjusted. If any component of
this unit is faulty or damaged, the entire automatic
dimming outside mirror unit must be replaced. (Refer
to 8 - ELECTRICAL/POWER MIRRORS/SIDEVIEW
MIRROR - DIAGNOSIS AND TESTING). Refer to
the appropriate wiring information. The wiring infor-
mation 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 con-
nectors, splices and grounds.
OPERATION
OPERATION - REAR VIEW MIRROR
The automatic day/night mirror switch allows the
driver a manual control of whether the automatic
dimming feature is operational. This switch is a
momentary rocker-type switch located on the lower
rear-facing surface of the mirror housing. When Auto
is selected, a Light-Emitting Diode (LED) on the mir-
ror housing just to the right of the switch illuminates
to indicate that automatic day/night mirror is turned
on. When Off is selected, the LED is turned off. The
mirror also senses the backup lamp circuit, and will
automatically disable its self-dimming feature when-
ever the transmission gear selector is in the Reverse
position.
A thin layer of electrochromatic material between
two pieces of conductive glass make up the face of
the mirror. Two photocell sensors are used to monitor
light levels and adjust the reflectance of the mirror.
The ambient photocell sensor faces forward, to detect
the outside light levels. The headlamp sensor is
located on the mirror housing just to the left of the
switch and facing rearward, to detect the light level
received at the rear window side of the mirror. When
the difference between the two light levels becomes
too great (the light level received at the rear of themirror is much higher than that at the front of the
mirror), the mirror begins to darken.
On models with an optional driver side automatic
dimming outside mirror, the signal to control the
dimming of that mirror is generated by the auto-
matic day/night inside rear view mirror circuitry.
That signal is then delivered to the driver side out-
side rear view mirror on a hard wired circuit.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the automatic day/night mirror system.
OPERATION - OUTSIDE REAR VIEW MIRROR
The automatic dimming outside mirror is operated
by the same controls and circuitry as the automatic
day/night mirror. When the automatic day/night mir-
ror is turned on or off, the automatic dimming out-
side mirror is likewise turned on or off. Like in the
automatic day/night mirror, a thin layer of electro-
chromatic material between two pieces of conductive
glass make up the face of the automatic dimming
outside mirror. However, the signal to control the
dimming of the outside mirror is generated by the
automatic day/night inside rear view mirror circuitry.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the automatic dimming outside mirror.
DIAGNOSIS AND TESTING - AUTOMATIC DAY /
NIGHT MIRROR
For complete circuit diagrams, refer to the appro-
priate 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 connec-
tors, splices and grounds.
(1) Check the fused ignition switch output (run/
start) fuse in the junction block. If OK, go to Step 2.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the junction block. If OK,
go to Step 3. If not OK, repair the open fused ignition
switch output (run/start) circuit to the ignition switch
as required.
(3) Disconnect the overhead wire harness connec-
tor from the automatic day/night mirror connector
receptacle. Check for battery voltage at the fused
ignition switch output (run/start) circuit cavity of the
overhead wire harness connector for the automatic
day/night mirror. If OK, go to Step 4. If not OK,
repair the open fused ignition switch output (run/
start) circuit to the fuse in the junction block as
required.
WJPOWER MIRRORS 8N - 13
AUTOMATIC DAY/NIGHT MIRROR (Continued)

²Passenger Airbag- The passenger airbag is
located on the instrument panel, beneath the instru-
ment panel top pad and above the glove box on the
passenger side of the vehicle.
²Passenger Knee Blocker- The passenger knee
blocker is a structural reinforcement that is integral
to and concealed within the glove box door.
²Side Impact Sensor- Two side impact sensors
are used on vehicles with the optional side curtain
airbags, one left side and one right side. One sensor
is located behind the B-pillar trim near the base of
each B-pillar.
²Side Curtain Airbag- In vehicles equipped
with this option, a side curtain airbag is located on
each inside roof side rail above the headliner, and
extends from the A-pillar to just beyond the C-pillar.
The ACM and the EMIC each contain a central
processing unit and programming that allow them to
communicate with each other using the Programma-
ble Communication Interface (PCI) data bus network.
This method of communication is used by the ACM
for control of the airbag indicator on all models
equipped with dual front airbags. (Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/
COMMUNICATION - DESCRIPTION).
Hard wired circuitry connects the supplemental
restraint system components to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system,
and to the supplemental restraint system compo-
nents through the use of a combination of soldered
splices, splice block connectors, and many different
types of wire harness terminal connectors and insu-
lators. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.
OPERATION
ACTIVE RESTRAINTS
The primary passenger restraints in this or any
other vehicle are the standard equipment factory-in-
stalled seat belts. Seat belts are referred to as an
active restraint because the vehicle occupants are
required to physically fasten and properly adjust
these restraints in order to benefit from them. See
the owner's manual in the vehicle glove box for more
information on the features, use and operation of all
of the factory-installed active restraints.PASSIVE RESTRAINTS
The passive restraints system is referred to as a
supplemental restraint system because they were
designed and are intended to enhance the protection
for the vehicle occupants of the vehicleonlywhen
used in conjunction with the seat belts. They are
referred to as passive systems because the vehicle
occupants are not required to do anything to make
them operate; however, the vehicle occupants must
be wearing their seat belts in order to obtain the
maximum safety benefit from the factory-installed
supplemental restraint systems.
The supplemental restraint system electrical cir-
cuits are continuously monitored and controlled by a
microprocessor and software contained within the
Airbag Control Module (ACM). An airbag indicator in
the ElectroMechanical Instrument Cluster (EMIC)
illuminates for about seven seconds as a bulb test
each time the ignition switch is turned to the On or
Start positions. Following the bulb test, the airbag
indicator is turned on or off by the ACM to indicate
the status of the supplemental restraint system. If
the airbag indicator comes on at any time other than
during the bulb test, it indicates that there is a prob-
lem in the supplemental restraint system electrical
circuits. Such a problem may cause airbags not to
deploy when required, or to deploy when not
required.
Deployment of the supplemental restraints
depends upon the angle and severity of an impact.
Deployment is not based upon vehicle speed; rather,
deployment is based upon the rate of deceleration as
measured by the forces of gravity (G force) upon the
impact sensors. When an impact is severe enough,
the microprocessor in the ACM signals the inflator
unit of the airbag module to deploy the airbag. Dur-
ing a frontal vehicle impact, the knee blockers work
in concert with properly fastened and adjusted seat
belts to restrain both the driver and the front seat
passenger in the proper position for an airbag deploy-
ment. The knee blockers also absorb and distribute
the crash energy from the driver and the front seat
passenger to the structure of the instrument panel.
Typically, the vehicle occupants recall more about
the events preceding and following a collision than
they have of an airbag deployment itself. This is
because the airbag deployment and deflation occur so
rapidly. In a typical 48 kilometer-per-hour (30 mile-
per-hour) barrier impact, from the moment of impact
until the airbags are fully inflated takes about 40
milliseconds. Within one to two seconds from the
moment of impact, the airbags are almost entirely
deflated. The times cited for these events are approx-
imations, which apply only to a barrier impact at the
given speed. Actual times will vary somewhat,
8O - 4 RESTRAINTSWJ
RESTRAINTS (Continued)

The ACM microprocessor continuously monitors all
of the supplemental restraint system electrical cir-
cuits to determine the system readiness. If the ACM
detects a monitored system fault, it sets an active
and stored Diagnostic Trouble Code (DTC) and sends
electronic messages to the EMIC over the PCI data
bus to turn on the airbag indicator. An active fault
only remains for the duration of the fault or in some
cases the duration of the current ignition switch
cycle, while a stored fault causes a DTC to be stored
in memory by the ACM. For some DTCs, if a fault
does not recur for a number of ignition cycles, the
ACM will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
The ACM receives battery current through two cir-
cuits, on a fused ignition switch output (run) circuit
through a fuse in the Junction Block (JB), and on a
fused ignition switch output (start-run) circuit
through a second fuse in the JB. The ACM is
grounded through a ground circuit and take out of
the instrument panel floor wire harness. This take
out has a single eyelet terminal connector secured by
a nut to a ground stud located behind the ACM
mount on the floor panel transmission tunnel. These
connections allow the ACM to be operational when-
ever the ignition switch is in the Start or On posi-
tions. The ACM also contains an energy-storage
capacitor. When the ignition switch is in the Start or
On positions, this capacitor is continually being
charged with enough electrical energy to deploy the
airbags for up to one second following a battery dis-
connect or failure. The purpose of the capacitor is to
provide backup supplemental restraint system pro-
tection in case there is a loss of battery current sup-
ply to the ACM during an impact.
Two sensors are contained within the ACM, an
electronic impact sensor and a safing sensor. The
ACM also monitors inputs from two remote front
impact sensors located on brackets on the inboard
sides of the right and left vertical members of the
radiator support near the front of the vehicle. The
electronic impact sensors are accelerometers that
sense the rate of vehicle deceleration, which provide
verification of the direction and severity of an
impact. On models equipped with optional side cur-
tain airbags, the ACM also monitors inputs from two
remote side impact sensors located near the base of
both the left and right inner B-pillars to control the
deployment of the side curtain airbag units.
The safing sensor is an electronic accelerometer
sensor within the ACM that provides an additional
logic input to the ACM microprocessor. The safingsensor is used to verify the need for an airbag
deployment by detecting impact energy of a lesser
magnitude than that of the primary electronic impact
sensors, and must exceed a safing threshold in order
for the airbags to deploy. The ACM also monitors a
Hall effect-type seat belt switch located in the buckle
of each front seat belt to determine whether the seat-
belts are buckled, and provides an input to the EMIC
over the PCI data bus to control the seatbelt indica-
tor operation based upon the status of the driver side
front seat belt switch. Vehicles with the optional side
curtain airbags feature a second safing sensor within
the ACM to provide confirmation to the ACM of side
impact forces. This second safing sensor is a bi-direc-
tional unit that detects impact forces from either side
of the vehicle.
Pre-programmed decision algorithms in the ACM
microprocessor determine when the deceleration rate
as signaled by the impact sensors and the safing sen-
sors indicate an impact that is severe enough to
require supplemental restraint system protection.
The ACM also determines the level of front airbag
deployment force required for each front seating posi-
tion based upon the status of the two seat belt switch
inputs and the severity of the monitored impact.
When the programmed conditions are met, the ACM
sends the proper electrical signals to deploy the mul-
tistage dual front airbags at the programmed force
levels, and to deploy either side curtain airbag.
The hard wired inputs and outputs for the ACM
may be diagnosed and tested using conventional
diagnostic tools and procedures. However, conven-
tional diagnostic methods will not prove conclusive in
the diagnosis of the ACM, the PCI data bus network,
or the electronic message inputs to and outputs from
the ACM. The most reliable, efficient, and accurate
means to diagnose the ACM, the PCI data bus net-
work, and the electronic message inputs to and out-
puts from the ACM requires the use of a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation.
REMOVAL
Two different Airbag Control Modules (ACM) are
available for this vehicle. For vehicles equipped with
the optional side curtain airbags, both ACM connec-
tor receptacles are black in color and the ACM con-
tains a second bi-directional safing sensor for the
side airbags. For vehicles not equipped with the
optional side curtain airbags, the ACM connector
receptacles are gray.
8O - 10 RESTRAINTSWJ
AIRBAG CONTROL MODULE (Continued)