lock CHRYSLER VOYAGER 2005 Service Manual

Page 498 of 2339

Service replacement clocksprings are shipped pre-
centered and with a molded plastic shield that snaps
onto the rotor over the release button. The release
button secures the centered clockspring rotor to the
clockspring case and the shield prevents the release
button from being inadvertently depressed during
shipment and handling, but the shield must be
removed from the clockspring after it is installed on
the steering column (Refer to 8 - ELECTRICAL/RE-
STRAINTS/CLOCKSPRING - STANDARD PROCE-
DURE).
The clockspring cannot be repaired. If the clock-
spring is faulty, damaged, or if the driver airbag has
been deployed, the clockspring must be replaced.
OPERATION
The clockspring is a mechanical electrical circuit
component that is used to provide continuous electri-
cal continuity between the fixed instrument panel
wire harness and the electrical components mounted
on or in the rotating steering wheel. The rotating
electrical components include the driver airbag, the
horn switch, the speed control switches, and the
remote radio switches, if the vehicle is so equipped.
The clockspring case is positioned and secured to the
upper steering column housing near the top of the
steering column. The connector receptacles on the
tail of the clockspring case connect the clockspring to
the vehicle electrical system through two connectors
from the instrument panel wire harness.
The clockspring rotor is movable and is keyed by
the tower formation that is molded onto the upper
surface of the rotor hub to an opening that is cast
into the steering wheel armature. Rubber bumper
blocks on either side of the clockspring tower forma-
tion eliminate contact noise between the clockspring
tower and the steering wheel. The lobe of the turn
signal cancel cam on the lower surface of the clock-
spring rotor hub contacts a turn signal cancel actua-
tor of the multi-function switch to provide automatic
turn signal cancellation. The yellow or black-sleeved
pigtail wires on the upper surface of the clockspring
rotor connect the clockspring to the driver airbag,
while a steering wheel wire harness connects the
connector receptacle on the upper surface of the
clockspring rotor to the horn switch and, if the vehi-
cle is so equipped, to the optional speed control
switches and remote radio switches on the steering
wheel.
The clockspring tape has travel limits and can be
damaged by being wound too tightly during full stop-
to-stop steering wheel rotation. To prevent this from
occurring, the clockspring is centered when it is
installed on the steering column. Centering the clock-
spring indexes the clockspring tape to the movable
steering components so that the tape can operatewithin its designed travel limits. However, if the
clockspring is removed from the steering column or if
the steering shaft is disconnected from the steering
gear, the clockspring spool can change position rela-
tive to the movable steering components and must be
re-centered following completion of the service or the
tape may be damaged (Refer to 8 - ELECTRICAL/
RESTRAINTS/CLOCKSPRING - STANDARD PRO-
CEDURE).
Service replacement clocksprings are shipped pre-
centered and with a plastic shield installed over the
clockspring release button. This shield should not be
removed and the release button should not be
depressed until the clockspring has been installed on
the steering column. If the release button is
depressed before the clockspring is installed on a
steering column, the clockspring centering procedure
must be performed (Refer to 8 - ELECTRICAL/RE-
STRAINTS/CLOCKSPRING - STANDARD PROCE-
DURE).
STANDARD PROCEDURE - CLOCKSPRING
CENTERING
If the rotating tape (wire coil) in the clockspring is
not positioned properly with the steering wheel and
the front wheels, the clockspring may fail. The fol-
lowing procedure MUST BE USED to center the
clockspring if it is not known to be properly posi-
tioned, or if the front wheels were moved from the
straight ahead position.
(1) Position steering wheel and front wheels
straight ahead.
(2) Release hood latch and open hood.
(3) Disconnect and isolate the battery negative
cable.
(4) Wait two minutes for the system reserve capac-
itor to discharge before beginning any airbag compo-
nent service.
(5) Remove driver airbag from steering wheel
(Refer to 8 - ELECTRICAL/RESTRAINTS/DRIVER
AIRBAG - REMOVAL).
(6) Disconnect wire connectors from back of driver
airbag.
(7) Disconnect the 2±way connector from remote
radio control harness (if equipped).
(8) Disconnect the 4±way harness connector from
the speed control (if equipped)/horn harness to the
clockspring.
(9) Remove steering wheel (Refer to 19 - STEER-
ING/COLUMN/STEERING WHEEL - REMOVAL).
(10) Rotate the clockspring rotor clockwise until
the rotor stops. Do not apply excessive force.
(11) From the end of travel, rotate the rotor two
turns counterclockwise until the wires end up at the
top.
RSRESTRAINTS8O-11
CLOCKSPRING (Continued)

Page 499 of 2339

(12) Install the steering wheel (Refer to 19 -
STEERING/COLUMN/STEERING WHEEL -
INSTALLATION).
(13) Connect the 4±way harness connector to the
speed control/horn harness to the clockspring.
(14) Connect the 2±way connector to the remote
radio control harness.
(15) Install the driver airbag (Refer to 8 - ELEC-
TRICAL/RESTRAINTS/DRIVER AIRBAG - INSTAL-
LATION). Torque the two screws to 10 N´m (90 in.
lbs.).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING). Personal injury or
death may result if the system test is not performed
properly.
REMOVAL
(1) Position steering wheel and front wheels
straight ahead.
(2) Release hood latch and open hood.
(3) Disconnect and isolate the battery negative
cable.
(4)
WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before beginning
any airbag system or component service. Failure to
do so may result in accidental airbag deployment,
personal injury or death.
(5) Remove driver airbag from steering wheel
(Refer to 8 - ELECTRICAL/RESTRAINTS/DRIVER
AIRBAG - REMOVAL).
(6) Disconnect wire connectors from back of driver
airbag.
(7) Disconnect the 2±way connector from remote
radio control harness.
(8) Disconnect the 4±way harness connector from
the speed control/horn harness to the clockspring.
(9) Remove steering wheel (Refer to 19 - STEER-
ING/COLUMN/STEERING WHEEL - REMOVAL).
(10) Remove steering column shrouds and discon-
nect traction control wire connector (if equipped)
(Refer to 19 - STEERING/COLUMN/LOWER
SHROUD - REMOVAL).
(11) Disconnect 4-way and 6-way connectors
between the clockspring and the instrument panel
wiring harness.
(12) Remove clockspring from column assembly by
removing the two retaining screws that attach the
clock spring to the column.
INSTALLATION
(1) Install the clockspring on the column.
(2) Connect the 4-way and 6-way connectors
between the clockspring and the instrument panel
wiring harness.
(3) Install the steering column shrouds and con-
nect traction control wire connector (if equipped)
(Refer to 19 - STEERING/COLUMN/LOWER
SHROUD - INSTALLATION).
(4) Install the steering wheel (Refer to 19 -
STEERING/COLUMN/STEERING WHEEL -
INSTALLATION).
(5) Connect the 4±way harness connector to the
speed control/horn harness to the clockspring.
(6) Connect the 2±way connector to the remote
radio control harness (if equipped).
(7) Install the driver airbag (Refer to 8 - ELEC-
TRICAL/RESTRAINTS/DRIVER AIRBAG - INSTAL-
LATION). Torque the two screws to 10 N´m (90 in.
lbs.).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
CURTAIN AIRBAG
DESCRIPTION
Curtain Airbags (Fig. 11) are available when it is
also equipped with dual front airbags. These airbags
are passive and inflatable, Supplemental Restraint
System (SRS) components, and vehicles with this
equipment can be readily identified by a molded
identification trim button with the ªSRS - AIRBAGº
logo (Fig. 12) located on the B-pillar and C-pillar
upper trim panels. This system is designed to reduce
injuries to the vehicle occupants in the event of a
side impact collision.
Curtain airbags have two individually controlled
curtain airbag units. These airbag units are con-
cealed and mounted above the headliner where they
are each secured to one of the roof side rails (Fig.
13). Each airbag cushion is contained within a fabric
wrap that extends along the roof rail from the A-pil-
lar at the front of the vehicle to just behind the
D-pillar at the rear of the vehicle. One tether extends
down the A-pillar from the front of the airbag cush-
ion, and a second tether extends to the roof rail at
the D-pillar. The end of the A-pillar tether is secured
to a slot in the sheet metal with a metal hook
retained by a bolt. The D-pillar tether is attached to
the d-pillar.
8O - 12 RESTRAINTSRS
CLOCKSPRING (Continued)

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INSTALLATION
(1) Position curtain airbag over retaining holes in
roof rail and firmly snap into place (Fig. 17).
(2) Install the curtain airbag retaining bolts (Fig.
17).
(3) Engage the side curtain airbag front tether in
the A-pillar and install retaining bolt (Fig. 16).
(4) Install the bolt in the curtain airbag inflator
mounting bracket (Fig. 18).
(5) Install the retaining bolts at the d-pillar (Fig.
19).
(6) Connect the curtain airbag squib connector
(Fig. 15).
(7) Install the headliner into the vehicle (Refer to
23 - BODY/INTERIOR/HEADLINER - INSTALLA-
TION).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(8) Verify vehicle and system operation.
(9) Close hood.
DRIVER AIRBAG
DESCRIPTION
The injection molded, thermoplastic driver airbag
protective trim cover is the most visible part of the
driver airbag. The driver airbag is located in the cen-
ter of the steering wheel, where it is secured to the
steering wheel armature. Concealed beneath the
driver airbag trim cover are the horn switch, thefolded airbag cushion, the airbag cushion retainer,
the airbag housing, the airbag inflator, and the
retainers that secure the inflator to the airbag hous-
ing. The airbag cushion, housing, and inflator are
secured within an integral receptacle molded into the
back of the trim cover.
The resistive membrane-type horn switch is
secured with heat stakes to the inside surface of the
driver airbag trim cover, between the trim cover and
the folded airbag cushion. The horn switch ground
pigtail wire has a female spade terminal connector
that receives a path to ground through a male spade
terminal that is integral to the driver airbag housing
stamping and is located near the upper right corner
on the back of the housing. The horn switch feed pig-
tail wire has a white, molded plastic insulator that is
secured by an integral retainer to a mounting hole
located near the lower left corner on the back of the
housing, and is connected to the vehicle electrical
system through a take out and connector of the steer-
ing wheel wire harness.
The airbag is a multistage unit that deploys with
less force than those previously used. The airbag
inflator is a dual-initiator, non-azide, pyrotechnic-
type unit with four mounting studs and is secured to
the stamped metal airbag housing using four hex
nuts with washers. Two keyed and color-coded con-
nector receptacles on the driver airbag inflator con-
nect the two inflator initiators to the vehicle
electrical system through two yellow or black-jack-
eted, two-wire pigtail harnesses of the clockspring.
The driver airbag, trim cover, and horn switch unit
cannot be repaired, and must be replaced if deployed
or in any way damaged.
OPERATION
The Driver Airbag Trim Cover contains the horn
switch, inflator device, and a fabric bag. The driver
airbag trim cover/horn switch is not serviced sepa-
rately from the driver airbag components.
When the front airbag system is deployed, the fol-
lowingMUSTbe replaced:
²Complete Steering Column Assembly
²Lower Steering Column Coupler
²Steering Wheel.
²Clockspring.
²Driver Airbag
²Passenger Airbag
²Knee Blocker Airbag
²Upper Instrument Panel with Pad
²Front Seat Belt Buckles, both driver and passen-
ger with integral tensioners.
Fig. 19 CURTAIN AIRBAG D-PILLAR ATTACHMENT
1 - CURTAIN AIRBAG D-PILLAR ATTACHMENT LOCATIONS
2 - D-PILLAR
3 - ROOF RAIL AT REAR QUARTER GLASS
8O - 16 RESTRAINTSRS
CURTAIN AIRBAG (Continued)

Page 504 of 2339

CARE OF UNDEPLOYED AIRBAGS
WARNING: Airbags must be stored in their original
special container until used for service. At no time
should a source of electricity be permitted near the
inflator on the back of an airbag. When carrying or
handling an undeployed airbag, the trim side of the
airbag should be pointing toward the body to mini-
mize possibility of injury if accidental deployment
occurs. Do not place undeployed airbag face down
on a solid surface, the airbag will propel into the air
if accidental deployment occurs.
REMOVAL
DEPLOYED AIRBAG
(1) Clean powder residue from interior of vehicle
(Fig. 4).
(2) Position steering wheel and front wheels
straight ahead.
(3) Release hood latch and open hood.
(4) Disconnect and isolate the battery negative
cable.
(5)
WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before beginning
any airbag system or component service. Failure to
do so may result in accidental airbag deployment,
personal injury or death.
(6) Remove two screws retaining driver airbag to
steering wheel.
(7) Disconnect wire connectors from back of driver
airbag.
(8) Disconnect the 2±way connector from remote
radio control harness.
(9) Disconnect the 4±way harness connector from
the speed control/horn harness to the clockspring.
(10) Remove steering wheel (Refer to 19 - STEER-
ING/COLUMN/STEERING WHEEL - REMOVAL).
(11) Remove steering column shrouds and discon-
nect traction control wire connector (if equipped)
(Refer to 19 - STEERING/COLUMN/LOWER
SHROUD - REMOVAL).
(12) Disconnect 4-way and 6-way connectors
between the clockspring and the instrument panel
wiring harness.
(13) Remove clockspring from column assembly by
removing the two retaining screws that attach the
clockspring to the column.
WARNING: The clockspring, steering wheel, and
complete steering column assembly w/lower steer-
ing column coupler must be replaced also in theevent of a driver airbag deployment. Personal injury
or death may result if not replaced.
UNDEPLOYED AIRBAG
(1) Release hood latch and open hood.
(2) Disconnect and isolate the battery negative
cable.
WARNING: Wait two minutes for the system reserve
capacitor to discharge before beginning any airbag
component service. Personal injury or death may
result.
(3) Remove two screws retaining driver airbag to
steering wheel.
(4) Disconnect wire connectors from back of driver
airbag (Fig. 20).
(5) Disconnect the 2±way connector from remote
radio control harness.
(6) Disconnect the 4±way harness connector from
the speed control/horn harness to the clockspring.
(7) Remove driver airbag from vehicle.
WARNING: When carrying or handling an unde-
ployed airbag, the trim side of the airbag should be
pointing toward the body to minimize the possibility
of injury if accidental deployment occurs. Do not
place undeployed airbag face down on a solid sur-
face, the airbag will propel into the air if accidental
deployment occurs. Failure to do this may result in
personal injury or death.
Fig. 20 DRIVER AIRBAG WIRE CONNECTIONS
1 - AIRBAG SQUIB CONNECTORS
2 - DRIVER AIRBAG
3 - HORN/SPEED CONTROL CONNECTOR
4 - CLOCK SPRING
RSRESTRAINTS8O-17
DRIVER AIRBAG (Continued)

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INSTALLATION
DEPLOYED AIRBAG
(1) Perform clean up procedure (Refer to 8 - ELEC-
TRICAL/RESTRAINTS - STANDARD PROCEDURE
- SERVICE AFTER AN AIRBAG DEPLOYMENT).
(2) Install a new steering column assembly and
lower steering column coupler (Refer to 19 - STEER-
ING/COLUMN - INSTALLATION).
(3) Install the new clockspring.
(4) Connect the 4-way and 6-way connectors
between the clockspring and the instrument panel
wiring harness.
(5) Install the steering column shrouds and con-
nect traction control wire connector (if equipped)
(Refer to 19 - STEERING/COLUMN/LOWER
SHROUD - INSTALLATION).
(6) Install the steering wheel (Refer to 19 -
STEERING/COLUMN/STEERING WHEEL -
INSTALLATION).
(7) Connect the 4±way harness connector to the
speed control/horn harness to the clockspring.
(8) Connect the 2±way connector to the remote
radio control harness.
(9) Install the driver airbag and the two screws
retaining the airbag. Tighten screws to 10 N´m (90
in. lbs.)
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
UNDEPLOYED AIRBAG
(1) Connect the harness connector on the driver
airbag trim cover (horn, speed controls) to the clock-
spring.
(2) Connect the squib connectors to the driver air-
bag.
(3) Position the driver airbag into the steering
wheel.
(4) Install the two screws retaining the airbag.
Tighten screws to 10 N´m (90 in. lbs.)
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
IMPACT SENSOR
DESCRIPTION
FRONT IMPACT SENSORS
There are two front impact sensors (Fig. 21), one
on the left, and one on the right front sides of the
vehicle. These sensors are mounted remotely from
the impact sensor that is internal to the Occupant
Restraint Controller (ORC). The right and left front
and side impact sensors are identical in construction
and calibration and each front impact sensor is
secured with two screws. The front impact sensors
are secured with two screws to the outboard sides of
the right and left front rail tips.
The impact sensor housing has an integral connec-
tor and two mounting ears, each with a metal sleeve
to provide crush protection. A cavity in the center of
the molded black plastic impact sensor housing con-
tains the electronic circuitry of the sensor which
includes an electronic communication chip and an
electronic impact sensor. Potting material fills the
cavity to seal and protect the internal electronic cir-
cuitry and components. The front impact sensors are
each connected to the vehicle electrical system
through the headlamp to dash wire harness.
The front impact sensors cannot be repaired or
adjusted and, if damaged or faulty, they must be
replaced. If a front impact sensor is faulty, only the
sensor needs to be replaced. If the sensor is damaged
or faulty, or if proper tightening torque of the screws
that secure the sensor to the bracket cannot be
achieved, the sensor and bracket must be replaced.
Refer to the proper body diagnostic information for
diagnosis and testing.
Fig. 21 FRONT IMPACT SENSOR
8O - 18 RESTRAINTSRS
DRIVER AIRBAG (Continued)

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WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(5) Verify vehicle and system operation.
(6) Close hood.
SLIDING DOOR OPENING MOUNTED
(1) Connect electrical connector (Fig. 27).
(2) Position sensor in vehicle (Fig. 27).
(3) Install the two retaining screws to the impact
sensor (Fig. 27). Torque screws to 7 N´m (62 in. lbs.).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(4) Verify vehicle and system operation.
(5) Close hood.
QUARTER PANEL MOUNTED
(1) Position sensor in vehicle (Fig. 28).
(2) Connect electrical connector (Fig. 28).
(3) Install the two retaining screws to the impact
sensor (Fig. 28). Torque screws to 7 N´m (62 in. lbs.).
(4) Install the quarter trim panel for the side of
the vehicle that you are replacing the side impact
sensor (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(5) Verify vehicle and system operation.
(6) Close hood.
KNEE BLOCKER AIRBAG
DESCRIPTION
The Knee Blocker Airbag (Fig. 29) is located on the
driver side of the vehicle beneath the instrument
panel under steering column cover (Fig. 30).
The knee blocker airbag includes one reaction plate
and one load plate, within which the cushion and
inflator are mounted and sealed. Following a knee
blocker airbag deployment, the knee blocker airbag
and instrument panel assembly must be replaced.
Refer to the proper diagnostic information for diagno-
sis and testing.
OPERATION
The knee blocker airbag is equipped with a single
inflator. When the Occupant Restraint Controller
(ORC) sends the proper electrical signals to the initi-
ator, the electrical energy generates enough heat to
initiate a small pyrotechnic charge which, in turn
ignites chemical pellets within the inflator. Once
ignited, these chemical pellets burn rapidly and pro-
duce a large quantity of inert gas. The inflator is
sealed to the back of the airbag housing and a dif-
fuser in the inflator directs all of the inert gas into
the airbag cushion, causing the cushion to inflate. As
the cushion inflates, the knee blocker airbag trim
deploy. Following an airbag deployment, the airbag
cushion quickly deflates by venting the inert gas
towards the instrument panel through vent holes
within the fabric used to construct the back panel of
the airbag cushion.
Some of the chemicals used to create the inert gas
may be considered hazardous while in their solid
state before they are burned, but they are securely
sealed within the airbag inflator. Typically, the poten-
tially hazardous chemicals are burned during an air-
bag deployment event.
WARNING: The inert gas that is produced when the
chemicals are burned is harmless. However, a small
amount of residue from the burned chemicals may
cause some temporary discomfort if it contacts the
skin, eyes, or breathing passages. If skin or eye irri-
tation is noted, rinse the affected area with plenty
of cool, clean water. If breathing passages are irri-
tated, move to another area where there is plenty of
clean, fresh air to breath. If the irritation is not alle-
viated by these actions, contact a physician.
Fig. 29 KNEE BLOCKER AIRBAG
8O - 22 RESTRAINTSRS
IMPACT SENSOR (Continued)

Page 510 of 2339

REMOVAL
(1) Open hood, disconnect and isolate the battery
negative cable.
(2)
WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before beginning
any airbag system or component service. Failure to
do so may result in accidental airbag deployment,
personal injury or death.
(3) Remove the steering column opening cover two
retaining screws (Fig. 31) and unsnap cover from
instrument panel (Refer to 23 - BODY/INSTRU-
MENT PANEL/STEERING COLUMN OPENING
COVER - REMOVAL).
(4) Disconnect the knee blocker airbag electrical
connector (Fig. 32).
(5) Remove five knee blocker airbag retaining bolts
from airbag (Fig. 33).
(6) Remove knee blocker airbag from vehicle.
INSTALLATION
(1) Place the knee blocker airbag into position in
the instrument panel opening (Fig. 33).
(2) Connect the one electrical connector (Fig. 32).
(3) Install the five knee blocker airbag retaining
bolts (Fig. 33).
(4) Position the steering column opening cover
over retaining slots and firmly snap into place (Fig.
31). Install the two retaining screws (Fig. 31) (Refer
to 23 - BODY/INSTRUMENT PANEL/STEERING
COLUMN OPENING COVER - INSTALLATION).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(5) Verify vehicle and system operation.
(6) Close hood.
Fig. 30 KNEE BLOCKER AIRBAG LOCATION
1 - KNEE BLOCKER AIRBAG 3 - UNDER STEERING COLUMN COVER RETAINING SCREWS
2 - UNDER STEERING C0LUMN COVER
RSRESTRAINTS8O-23
KNEE BLOCKER AIRBAG (Continued)

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Fig. 31 STEERING COLUMN OPENING COVER
1 - KNEE BLOCKER AIRBAG 3 - UNDER STEERING COLUMN COVER RETAINING SCREWS
2 - UNDER STEERING C0LUMN COVER
Fig. 32 KNEE BLOCKER AIRBAG ELECTRICAL
CONNECTOR
1 - KNEE BLOCKER AIRBAG
2 - INSTRUMENT PANEL
3 - KNEE BLOCKER AIRBAG ELECTRICAL CONNECTOR
Fig. 33 KNEE BLOCKER AIRBAG - REMOVE/
INSTALL
1 - KNEE BLOCKER AIRBAG RETAINING SCREWS
2 - KNEE BLOCKER AIRBAG
3 - KNEE BLOCKER AIRBAG ELECTRICAL CONNECTOR
4 - INSTRUMENT PANEL
8O - 24 RESTRAINTSRS
KNEE BLOCKER AIRBAG (Continued)

Page 512 of 2339

OCCUPANT CLASSIFICATION
MODULE
DESCRIPTION
The Occupant Classification Module (OCM) (Fig.
34) is secured with two screws to a stamped steel
mounting bracket welded onto the underside of the
passenger front seat cushion frame near the inboard
front corner (Fig. 35). Concealed within a hollow in
the center of the molded plastic OCM housing is a
microprocessor and the other electronic circuitry of
the module. The module housing is sealed to enclose
and protect the internal electronic circuitry. The
OCM software is flash programmable.
A non-calibrated OCM is the only component of the
Occupant Classification System (OCS) that is avail-
able for separate service replacement. The OCS com-
ponents of the passenger side front seat cushion
including the cushion frame, insulator pad, seat
weight bladder and pressure sensor, seat cushion
foam, wiring harness and the OCM are a factory-cal-
ibrated and assembled unit. Once this unit is con-
nected to a vehicle electrically, the calibration
settings are uploaded from the calibrated OCM and
stored in the memory of the Occupant Restraint Con-
troller (ORC). If only the OCM is subsequently
replaced, the new, non-calibrated OCM learns the
proper calibration settings from the ORC after it is
connected to the vehicle electrically.The OCM cannot be adjusted or repaired and, if
damaged or faulty, it must be replaced. The compo-
nents of the passenger front seat cushion are ser-
viced only as a factory-calibrated, assembled and
tamper-evident unit. Only the OCM and the seat
cushion trim are available for separate service
replacement. Once a service replacement package has
been installed in a vehicle, the OCM can thereafter
be serviced only by replacing the entire passenger
front seat cushion with another complete service
replacement package.
OPERATION
The microprocessor in the Occupant Classification
Module (OCM) contains the Occupant Classification
System (OCS) logic circuits. The OCM uses On-Board
Diagnostics (OBD) and can communicate with other
electronic modules in the vehicle as well as with a
scan tool using the Programmable Communications
Interface (PCI) data bus network. This method of
communication is also used for OCS diagnosis and
testing through the 16-way Data Link Connector
(DLC), located on the driver side lower edge of the
instrument panel.
The OCM provides a nominal five volts to both the
pressure sensor of the seat weight bladder beneath
the passenger front seat cushion and to the belt ten-
sion sensor on the passenger front seat belt lower
Fig. 34 OCCUPANT CLASSIFICATION MODULE
(OCM) - TYPICAL
1 - OCCUPANT CLASSIFICATION MODULE
2 - CONNECTOR LOCK TOWER
3 - CONNECTOR RECEPTACLE
4 - MOUNTING TAB (2)
Fig. 35 OCM LOCATION
1 - OCCUPANT CLASSIFICATION MODULE (OCM)
2 - LOCK TOWER
3 - LOCK PIN
4 - CONNECTOR
5 - SCREW (2)
6 - BRACKET
RSRESTRAINTS8O-25

Page 513 of 2339

anchor. The OCM then monitors the return voltage
from each of the sensors. The bladder pressure sen-
sor input allows the OCM to determine whether the
passenger front seat is occupied and the relative size
of the occupant by providing a weight-sensing refer-
ence to the load on the seat cushion. The belt tension
sensor provides an additional logic input to the OCM
microprocessor that allows it to distinguish between
the lower seat belt cinch loads of a belted occupant
and the higher loads associated with a belted child
seat.
Pre-programmed decision algorithms and OCS cal-
ibration allow the OCM microprocessor to determine
when the seat cushion load as signaled by the blad-
der pressure sensor and the seat belt cinch load as
signaled by the belt tension sensor indicate that pas-
senger airbag protection is appropriate. When the
programmed conditions are met, the OCM sends the
proper electronic occupant classification messages
over the PCI data bus to the Occupant Restraint
Controller (ORC), and the ORC enables or disables
the deployment circuits for the passenger front sup-
plemental restraints. The ORC also provides a con-
trol output for the Passenger Airbag Disabled (PAD)
indicator in the instrument panel center stack, based
upon the electronic occupant classification messages
it receives from the OCM.
The OCM microprocessor continuously monitors all
of the OCS electrical circuits and components to
determine the system readiness. If the OCM detects
a monitored system fault, it sets an active and stored
Diagnostic Trouble Code (DTC) and sends the appro-
priate electronic messages to the ORC over the PCI
data bus. Then the ORC sets a DTC and sends mes-
sages to control the airbag indicator operation
accordingly. An active fault only remains for the
duration of the fault, or in some cases for the dura-
tion of the current ignition switch cycle, while a
stored fault causes a DTC to be stored in memory by
the OCM and the ORC. For some DTC's, if a fault
does not recur for a number of ignition cycles, the
OCM will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
The OCM receives battery current from an IPM
high side driver (Run/Start). The OCM receives
ground through a ground circuit of the body wire
harness, which it shares with the ORC. These con-
nections allow the OCM to be operational whenever
the ignition switch is in the Start or ON positions.
To diagnose and test the OCS, use a scan tool and
the appropriate diagnostic information.
REMOVAL
Once any of the original factory-installed compo-
nents except the Occupant Classification Module(OCM) have been replaced with the service replace-
ment package components, the OCM can only be ser-
viced by replacing the entire passenger front seat
cushion unit with another complete service replace-
ment package (Refer to 23 - BODY/SEATS/SEAT
CUSHION - FRONT - REMOVAL).
WARNING: Never replace both the Occupant
Restraint Controller (ORC) and the Occupant Clas-
sification Module (OCM) at the same time. If both
require replacement, replace one, then perform the
Airbag System test (Refer to 8 - ELECTRICAL/RE-
STRAINTS - DIAGNOSIS AND TESTING - AIRBAG
SYSTEM) before replacing the other. Both the ORC
and the OCM store Occupant Classification System
(OCS) calibration data, which they transfer to one
another when one of them is replaced. If both are
replaced at the same time, an irreversible fault will
be set in both modules and the OCS may malfunc-
tion and result in personal injury or death.
(1) Disconnect and isolate the battery negative
cable.
(2)
WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before beginning
any airbag system or component service. Failure to
do so may result in accidental airbag deployment,
personal injury or death.
(3) Reach under the front edge of the passenger
side front seat cushion to access and remove the lock
pin from the connector lock tower on the Occupant
Classification Module (OCM) (Fig. 36).
(4) Disconnect the passenger front seat wire har-
ness connector for the OCM.
(5) Remove the two screws that secure the OCM to
the OCM bracket.
(6) Remove the OCM from under the passenger
front seat.
INSTALLATION
WARNING: To avoid personal injury or death on
vehicles equipped with the Occupant Classification
System (OCS), only the Occupant Classification
Module (OCM) and the seat cushion trim may be
serviced separately. All other components of the
passenger front seat cushion must be serviced only
as a complete factory-calibrated, assembled and
tamper-evident service replacement package.
Once any of the original factory-installed compo-
nents except the OCM have been replaced with the
service replacement package components, the OCM
can only be serviced by replacing the entire passen-
8O - 26 RESTRAINTSRS
OCCUPANT CLASSIFICATION MODULE (Continued)

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