1998 DODGE RAM 1500 Turn signal

resistance of the input from the on/off switch. The
ACM will also set and/or store a DTC for faults it
detects in the passenger airbag on/off switch circuits,
and will turn on the airbag indicator in the EMIC if
a fault has been detected.
The ACM receives battery current through two cir-
cuits; a fused ignition switch output (run) circuit
through a fuse in the Integrated Power Module
(IPM), and a fused ignition switch output (run-start)
circuit through a second fuse in the IPM. The ACM
receives ground through a ground circuit and take
out of the instrument panel wire harness. This take
out has a single eyelet terminal connector that is
secured by a ground screw to the instrument panel
support structure. These connections allow the ACM
to be operational whenever the ignition switch is in
the Start or On positions.
The ACM also contains an energy-storage capaci-
tor. When the ignition switch is in the Start or On
positions, this capacitor is continually being charged
with enough electrical energy to deploy the supple-
mental restraint components for up to one second fol-
lowing a battery disconnect or failure. The purpose of
the capacitor is to provide backup supplemental
restraint system protection in case there is a loss of
battery current supply to the ACM during an impact.
Two sensors are contained within the ACM, an
electronic impact sensor and a safing sensor. 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 within both the
left and right B-pillars to control 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 safing
sensor is used to verify the need for a supplemental
restraint 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. Vehicles equipped
with optional side curtain airbags feature a second
safing sensor within the ACM to provide confirma-
tion to the ACM microprocessor of side impact forces.
This second safing sensor is a bi-directional 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
and, based upon the severity of the monitored impact
and the status of the passenger airbag on/off switchinput, determines the level of front airbag deploy-
ment force required for each front seating position.
When the programmed conditions are met, the ACM
sends the proper electrical signals to deploy the dual
multistage front airbags at the programmed force
levels, the front seat belt tensioners and, if the vehi-
cle is so equipped, either side curtain airbag unit.
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
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE SUPPLEMENTAL RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, AIRBAG, SEAT BELT
TENSIONER, IMPACT SENSOR, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
DISCONNECT AND ISOLATE THE BATTERY NEGA-
TIVE (GROUND) CABLE, THEN WAIT TWO MINUTES
FOR THE SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE SUPPLEMENTAL RESTRAINT SYSTEM.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, NEVER STRIKE OR DROP THE AIRBAG
CONTROL MODULE, AS IT CAN DAMAGE THE
IMPACT SENSOR OR AFFECT ITS CALIBRATION.
THE AIRBAG CONTROL MODULE CONTAINS THE
IMPACT SENSOR, WHICH ENABLES THE SYSTEM
TO DEPLOY THE SUPPLEMENTAL RESTRAINTS. IF
AN AIRBAG CONTROL MODULE IS ACCIDENTALLY
DROPPED DURING SERVICE, THE MODULE MUST
BE SCRAPPED AND REPLACED WITH A NEW UNIT.
FAILURE TO OBSERVE THIS WARNING COULD
RESULT IN ACCIDENTAL, INCOMPLETE, OR
IMPROPER SUPPLEMENTAL RESTRAINT DEPLOY-
MENT.
8O - 12 RESTRAINTSDR
AIRBAG CONTROL MODULE (Continued)

INSTALLATION
The following procedure applies only to the rear
seat upper child tether straps used on quad cab mod-
els. The child restraint anchors used in other models
and locations are integral to other components and
cannot be serviced separately.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, DURING AND FOLLOWING ANY SEAT BELT
OR CHILD RESTRAINT ANCHOR SERVICE, CARE-
FULLY INSPECT ALL SEAT BELTS, BUCKLES,
MOUNTING HARDWARE, RETRACTORS, TETHER
STRAPS, AND ANCHORS FOR PROPER INSTALLA-
TION, OPERATION, OR DAMAGE. REPLACE ANY
BELT THAT IS CUT, FRAYED, OR TORN.
STRAIGHTEN ANY BELT THAT IS TWISTED.
TIGHTEN ANY LOOSE FASTENERS. REPLACE ANY
BELT THAT HAS A DAMAGED OR INOPERATIVE
BUCKLE OR RETRACTOR. REPLACE ANY BELT
THAT HAS A BENT OR DAMAGED LATCH PLATE
OR ANCHOR PLATE. REPLACE ANY CHILD
RESTRAINT ANCHOR OR THE UNIT TO WHICH THE
ANCHOR IS INTEGRAL THAT HAS BEEN BENT OR
DAMAGED. NEVER ATTEMPT TO REPAIR A SEAT
BELT OR CHILD RESTRAINT COMPONENT.
ALWAYS REPLACE DAMAGED OR FAULTY SEAT
BELT AND CHILD RESTRAINT COMPONENTS WITH
THE CORRECT, NEW AND UNUSED REPLACEMENT
PARTS LISTED IN THE DAIMLERCHRYSLER MOPAR
PARTS CATALOG.
(1) Position the child tether strap onto the upper
cab back panel reinforcement (Fig. 16).
(2) Install and tighten the screw that secures the
child tether strap to the upper cab back panel rein-
forcement. Tighten the screw to 14 N´m (10 ft. lbs.).(3) Reinstall the rear seat into the vehicle. (Refer
to 23 - BODY/SEATS/SEAT - REAR - INSTALLA-
TION).
CLOCKSPRING
DESCRIPTION
The clockspring assembly is secured with two
screws onto the multi-function switch mounting
housing near the top of the steering column behind
the steering wheel (Fig. 17). The clockspring consists
of a flat, round molded plastic case with a stubby tail
that hangs below the steering column (Fig. 18). The
tail contains two connector receptacles that face
toward the instrument panel. Within the plastic case
is a spool-like molded plastic rotor with a large
exposed hub. The upper surface of the rotor hub has
a large center hole, two large flats, an engagement
dowel with a yellow rubber boot, two short pigtail
wires with connectors, and two connector receptacles
that face toward the steering wheel.
The lower surface of the rotor hub has a molded
plastic turn signal cancel cam with two lobes that is
keyed to the rotor and is secured there with four
integral snap features. Within the plastic case and
wound around the rotor spool is a long ribbon-like
tape that consists of several thin copper wire leads
sandwiched between two thin plastic membranes.
The outer end of the tape terminates at the connector
Fig. 16 Child Tether Strap - Quad Cab
1 - TETHER STRAP (3)
2 - CAB BACK PANEL
3 - SCREW (3)
Fig. 17 Clockspring
1 - PIGTAIL WIRE (2)
2 - LOCATING TAB
3 - LOCKING PIN
4 - MOUNTING TAB (2)
5 - UPPER CONNECTOR RECEPTACLE (2)
6 - LABEL
7 - ENGAGEMENT DOWEL & BOOT
8 - CASE
9 - CENTERING ARROWS
10 - ROTOR
8O - 18 RESTRAINTSDR
CHILD RESTRAINT ANCHOR (Continued)

receptacles that face the instrument panel, while the
inner end of the tape terminates at the pigtail wires
and connector receptacles on the hub of the clock-
spring rotor that face the steering wheel.
Service replacement clocksprings are shipped pre-
centered and with a molded plastic locking pin that
snaps into a receptacle on the rotor and is engaged
between two tabs on the upper surface of the rotor
case. The locking pin secures the centered clock-
spring rotor to the clockspring case during shipment
and handling, but must be removed from the clock-
spring after it is installed on the steering column.
(Refer to 8 - ELECTRICAL/RESTRAINTS/CLOCK-
SPRING - STANDARD PROCEDURE - CLOCK-
SPRING CENTERING).
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. On this model
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 multi-function switch mounting hous-
ing near the top of the steering column. The connec-
tor receptacles on the tail of the fixed clockspring
case connect the clockspring to the vehicle electrical
system through two take outs with connectors from
the instrument panel wire harness.The clockspring rotor is movable and is keyed by
an engagement dowel that is molded onto the rotor
hub between two fins that are cast into the lower
surface of the steering wheel armature. A yellow rub-
ber boot is installed over the engagement dowel to
eliminate contact noise between the dowel and the
steering wheel. The two lobes on the turn signal can-
cel cam on the lower surface of the clockspring rotor
hub contact a turn signal cancel actuator of the
multi-function switch to provide automatic turn sig-
nal cancellation.
Two short, yellow-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 two connector recep-
tacles on the upper surface of the clockspring rotor to
the horn switch feed pigtail wire connector and, if
the vehicle is so equipped, to the optional speed con-
trol and remote radio switches on the steering wheel.
Like the clockspring in a timepiece, 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 clockspring indexes
the clockspring tape to the movable steering compo-
nents so that the tape can operate within 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 relative to the
movable steering components. The clockspring must
be re-centered following completion of this service or
the tape may be damaged.
Service replacement clocksprings are shipped pre-
centered and with a plastic locking pin installed.
This locking pin should not be removed until the
clockspring has been installed on the steering col-
umn. If the locking pin is removed before the clock-
spring is installed on a steering column, the
clockspring centering procedure must be performed.
(Refer to 8 - ELECTRICAL/RESTRAINTS/CLOCK-
SPRING - STANDARD PROCEDURE - CLOCK-
SPRING CENTERING).
STANDARD PROCEDURE - CLOCKSPRING
CENTERING
The clockspring is designed to wind and unwind
when the steering wheel is rotated, but is only
designed to rotate the same number of turns (about
five complete rotations) as the steering wheel can be
turned from stop to stop. Centering the clockspring
indexes the clockspring tape to other steering compo-
nents so that it can operate within its designed
travel limits. The rotor of a centered clockspring can
be rotated two and one-half turns in either direction
Fig. 18 Turn Signal Cancel Cam
1 - LOCKING PIN
2 - CLOCKSPRING CASE
3 - CANCEL CAM
4 - LOWER CONNECTOR RECEPTACLE (2)
DRRESTRAINTS 8O - 19
CLOCKSPRING (Continued)

by the ACM to suit the monitored impact conditions
by providing one of three delay intervals between the
electrical signals provided to the two initiators. The
longer the delay between these signals, the less force-
fully the airbag will deploy.
When the ACM sends the proper electrical signals
to each initiator, 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 produce a large quantity of inert gas.
The inflator is sealed to the back of the airbag hous-
ing and a diffuser in the inflator directs all of the
inert gas into the airbag cushion, causing the cushion
to inflate. As the cushion inflates, the driver airbag
trim cover will split at predetermined breakout lines,
then fold back out of the way along with the horn
switch unit. Following an airbag deployment, the air-
bag cushion quickly deflates by venting the inert gas
towards the instrument panel through vent holes
within the fabric used to construct the back (steering
wheel side) 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, both ini-
tiators are used and all potentially hazardous chem-
icals are burned during an airbag deployment event.
However, it is possible for only one initiator to be
used during a deployment due to an airbag system
fault; therefore, it is necessary to always confirm
that both initiators have been used in order to avoid
the improper disposal of potentially live pyrotechnic
or hazardous materials. (Refer to 8 - ELECTRICAL/
RESTRAINTS - STANDARD PROCEDURE - SER-
VICE AFTER A SUPPLEMENTAL RESTRAINT
DEPLOYMENT).
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 irritation is noted,
rinse the affected area with plenty of cool, clean
water. If breathing passages are irritated, move to
another area where there is plenty of clean, fresh air
to breath. If the irritation is not alleviated by these
actions, contact a physician.
REMOVAL
The following procedure is for replacement of a
faulty or damaged driver airbag. If the airbag is
faulty or damaged, but not deployed, review the rec-
ommended procedures for handling non-deployed
supplemental restraints. (Refer to 8 - ELECTRICAL/
RESTRAINTS - STANDARD PROCEDURE - HAN-
DLING NON-DEPLOYED SUPPLEMENTALRESTRAINTS). If the driver airbag has been
deployed, review the recommended procedures for
service after a supplemental restraint deployment
before removing the airbag from the vehicle. (Refer to
8 - ELECTRICAL/RESTRAINTS - STANDARD PRO-
CEDURE - SERVICE AFTER A SUPPLEMENTAL
RESTRAINT DEPLOYMENT).
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE SUPPLEMENTAL RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, AIRBAG, SEAT BELT
TENSIONER, IMPACT SENSOR, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
DISCONNECT AND ISOLATE THE BATTERY NEGA-
TIVE (GROUND) CABLE, THEN WAIT TWO MINUTES
FOR THE SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE SUPPLEMENTAL RESTRAINT SYSTEM.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, WHEN REMOVING A DEPLOYED AIRBAG,
RUBBER GLOVES, EYE PROTECTION, AND A
LONG-SLEEVED SHIRT SHOULD BE WORN. THERE
MAY BE DEPOSITS ON THE AIRBAG CUSHION AND
OTHER INTERIOR SURFACES. IN LARGE DOSES,
THESE DEPOSITS MAY CAUSE IRRITATION TO THE
SKIN AND EYES.
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the system capacitor to
discharge before further service.
(2) From the underside of the steering wheel,
remove the two screws that secure the driver airbag
to the steering wheel armature (Fig. 23).
(3) Pull the driver airbag away from the steering
wheel far enough to access the three electrical con-
nections on the back of the airbag housing (Fig. 24).
(4) Disconnect the steering wheel wire harness
connector for the horn switch from the horn switch
feed pigtail wire connector, which is located on the
back of the driver airbag housing.
CAUTION: Do not pull on the clockspring pigtail
wires or pry on the connector insulator to disen-
gage the connector from the driver airbag inflator
connector receptacle. Improper removal of these
pigtail wires and their connector insulators can
result in damage to the airbag circuits or connector
insulators.
8O - 24 RESTRAINTSDR
DRIVER AIRBAG (Continued)

OPERATION
The multistage passenger airbag is deployed by
electrical signals generated by the Airbag Control
Module (ACM) through the passenger airbag squib 1
and squib 2 circuits to the two initiators in the air-
bag inflator. By using two initiators, the airbag can
be deployed at multiple levels of force. The force level
is controlled by the ACM to suit the monitored
impact conditions by providing one of four delay
intervals between the electrical signals provided to
the two initiators. The longer the delay between
these signals, the less forcefully the airbag will
deploy.
When the ACM sends the proper electrical signals to
each initiator, 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 airbag cushion and a diffuser in the infla-
tor directs all of the inert gas into the airbag cushion,
causing the cushion to inflate. As the cushion inflates,
the passenger airbag door will split at predetermined
tear seam lines concealed on the inside surface of the
door, then the door will pivot up over the top of the
instrument panel and out of the way. Following an air-
bag deployment, the airbag cushion quickly deflates by
venting the inert gas through vent holes within the
fabric used to construct the back (instrument panel
side) of the airbag cushion.
Typically, both initiators are used during an airbag
deployment event. However, it is possible for only one
initiator to be used during a deployment due to an
airbag system fault; therefore, it is necessary to
always confirm that both initiators have been used in
order to avoid the improper disposal of potentially
live pyrotechnic materials. (Refer to 8 - ELECTRI-
CAL/RESTRAINTS - STANDARD PROCEDURE -
SERVICE AFTER A SUPPLEMENTAL RESTRAINT
DEPLOYMENT).
REMOVAL
The following procedure is for replacement of a
faulty or damaged passenger airbag. If the airbag is
faulty or damaged, but not deployed, review the rec-
ommended procedures for handling non-deployed
supplemental restraints. (Refer to 8 - ELECTRICAL/
RESTRAINTS - STANDARD PROCEDURE - HAN-
DLING NON-DEPLOYED SUPPLEMENTAL
RESTRAINTS). If the passenger airbag has been
deployed, review the recommended procedures for
service after a supplemental restraint deployment
before removing the airbag from the vehicle. (Refer to
8 - ELECTRICAL/RESTRAINTS - STANDARD PRO-
CEDURE - SERVICE AFTER A SUPPLEMENTAL
RESTRAINT DEPLOYMENT).WARNING: TO AVOID PERSONAL INJURY OR
DEATH, ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE SUPPLEMENTAL RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, AIRBAG, SEAT BELT
TENSIONER, IMPACT SENSOR, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
DISCONNECT AND ISOLATE THE BATTERY NEGA-
TIVE (GROUND) CABLE, THEN WAIT TWO MINUTES
FOR THE SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE SUPPLEMENTAL RESTRAINT SYSTEM.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, WHEN REMOVING A DEPLOYED AIRBAG,
RUBBER GLOVES, EYE PROTECTION, AND A
LONG-SLEEVED SHIRT SHOULD BE WORN. THERE
MAY BE DEPOSITS ON THE AIRBAG UNIT AND
OTHER INTERIOR SURFACES. IN LARGE DOSES,
THESE DEPOSITS MAY CAUSE IRRITATION TO THE
SKIN AND EYES.
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the system capacitor to
discharge before further service.
(2) Remove the lower surround from the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/LOWER SURROUND - REMOVAL).
(3) Remove the screw that secures the mounting
tab of the panel outlet housing to the upper glove box
opening reinforcement (Fig. 36).
(4) Remove the six screws that secure the inboard
and lower flanges of the passenger airbag door to the
instrument panel.
Fig. 36 Passenger Airbag Door Screws
1 - PASSENGER AIRBAG DOOR
2 - PANEL OUTLET SCREW (1)
3 - GLOVE BOX OPENING UPPER REINFORCEMENT
4 - DOOR SCREW (6)
8O - 40 RESTRAINTSDR
PASSENGER AIRBAG (Continued)

OPERATION
The seat belt tension reducer is controlled by a
ground signal received from the seat belt switch on
the seat belt switch sense circuit and a battery cur-
rent signal received from the ignition switch on the
fused ignition switch output (run-accessory) circuit.
When the seat belt switch is closed (the driver side
front seat belt is fastened) and the ignition switch is
in the On or Accessory positions, the seat belt tension
reducer solenoid is energized. When the solenoid is
energized, it actuates a mechanism within the driver
side front outboard seat belt retractor to reduce the
normal recoil spring tension exerted by the retractor
spool, which is designed to reel in the seat belt web-
bing onto the spool. When the driver side seat belt is
unbuckled or if the ignition switch is turned to any
position except On or Accessory, the tension reducer
solenoid is de-energized and the normal recoil spring
tension of the retractor is restored.
The action of the seat belt tension reducer results
in improved seat belt comfort for the driver. Reducing
the seat belt retractor recoil spring tension is desir-
able on standard cab models of this vehicle and not
on the quad cab model due to the different mounting
position required for the seat belt turning loop on the
B-pillar relative to the driver's seat position on the
standard cab model. The seat belt tension reducer
may be diagnosed using conventional diagnostic tools
and methods.
DIAGNOSIS AND TESTING - SEAT BELT
TENSION REDUCER
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.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE SUPPLEMENTAL RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, AIRBAG, SEAT BELT
TENSIONER, IMPACT SENSOR, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
DISCONNECT AND ISOLATE THE BATTERY NEGA-
TIVE (GROUND) CABLE, THEN WAIT TWO MINUTES
FOR THE SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE SUPPLEMENTAL RESTRAINT SYSTEM.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT.(1) Disconnect and isolate the battery negative
cable. Disconnect the body wire harness connector for
the seat belt tension reducer from the tension
reducer connector receptacle on the driver side front
outboard seat belt and retractor unit. Using an ohm-
meter, measure the resistance between the seat belt
switch sense circuit terminal pin and the fused igni-
tion switch output (run-accessory) circuit terminal
pin in the tension reducer connector receptacle on
the retractor. Resistance through the tension reducer
solenoid coil should be 53 ohms at 20É C (68É F). If
OK, go to Step 2. If not OK, replace the faulty driver
side front outboard seat belt and retractor unit.
(2) Check for continuity between the seat belt
switch sense circuit cavity of the body wire harness
connector for the seat belt tension reducer and a good
ground. There should be continuity with the driver
side front seat belt buckled, and no continuity with
the driver side front seat belt unbuckled. If OK, go to
Step 3. If not OK, repair the shorted or open seat
belt switch sense circuit between the tension reducer
and the seat belt switch as required.
(3) Reconnect the battery negative cable. Check for
battery current at the fused ignition switch output
(run-accessory) circuit of the body wire harness con-
nector for the seat belt tension reducer. There should
be battery current with the ignition switch in the On
or Accessory positions, and no battery current with
the ignition switch in any other position. If not OK,
repair the shorted or open fused ignition switch out-
put (run-accessory) circuit between the tension
reducer and the ignition switch as required.
8O - 54 RESTRAINTSDR
SEAT BELT TENSION REDUCER (Continued)

(4) Install the upper screw that secures the seat
belt turning loop height adjuster to the upper B-pil-
lar, then tighten both the upper and lower screws to
40 N´m (29 ft. lbs.).
(5) Reinstall the upper trim onto the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
UPPER TRIM - INSTALLATION).
(6) Position the seat belt turning loop onto the
height adjuster on the upper inner B-pillar.
(7) Install and tighten the screw that secures the
seat belt turning loop to the height adjuster. Tighten
the screw to 40 N´m (29 ft. lbs.).
(8) Engage the lower snap features of the new trim
cover over the front outboard seat belt turning loop
and, using hand pressure, press firmly and evenly on
the top of the trim cover until it snaps into place.
SIDE CURTAIN AIRBAG
DESCRIPTION
Optional side curtain airbags are available for this
model when it is also equipped with dual front air-
bags. These airbags are passive, inflatable, Supple-
mental Restraint System (SRS) components, and
vehicles with this equipment can be readily identified
by a molded identification trim button with the ªSRS
- AIRBAGº logo located on the headliner above each
A-pillar, and above each B-pillar on quad cab models
(Fig. 51). This system is designed to reduce injuries
to the vehicle occupants in the event of a side impact
collision.
Vehicles equipped with side curtain airbags have
two individually controlled curtain airbag units.
These airbag units are concealed and mounted above
the headliner where they are each secured to one of
the roof side rails (Fig. 52). Each folded airbag cush-
ion is contained within a long extruded plastic chan-
nel that extends along the roof rail from the A-pillarat the front of the vehicle to just behind the B-pillar
on standard cab models, and to just behind the C-pil-
lar on quad cab models. A tether extends down the
A-pillar from the front of the airbag cushion, where it
is retained to the pillar with plastic push-in routing
clips and it is secured to the base of the A-pillar near
the belt line with a screw.
The hybrid-type inflator for each airbag is secured
to the roof rail at the rear of the airbag unit behind
the B-pillar (standard cab) or C-pillar (quad cab), and
is connected to the airbag cushion by a long tubular
manifold. The inflator bracket and the extruded air-
bag cushion channel are located with plastic push-in
fasteners to the roof rail, then secured with screws to
spring nuts located in the roof rail. A two-wire take
out of the body wire harness with a keyed and
latched connector insulator connects directly to an
integral receptacle on the inflator initiator.
The side curtain airbag unit cannot be adjusted or
repaired and must be replaced if deployed, faulty, or
in any way damaged. Once a side curtain airbag has
been deployed, the complete airbag unit, the head-
liner, the upper A, B, and C-pillar trim, and all other
visibly damaged components must be replaced.
OPERATION
Each side curtain airbag is deployed individually
by an electrical signal generated by the Airbag Con-
trol Module (ACM) to which it is connected through
left or right curtain airbag line 1 and line 2 (or
squib) circuits. The hybrid-type inflator assembly for
each airbag contains a small canister of highly com-
Fig. 51 SRS Logo
Fig. 52 Side Curtain Airbag
1 - WIRE HARNESS CONNECTOR
2 - B-PILLAR (STD CAB) OR C-PILLAR (QUAD CAB)
3 - INFLATOR
4 - MANIFOLD
5 - ROOF SIDE RAIL
6 - A-PILLAR
7 - TETHER
8 - CHANNEL
8O - 56 RESTRAINTSDR
SEAT BELT TURNING LOOP ADJUSTER (Continued)

5.9L Diesel With Manual Trans.
The speed control system is fully electronically con-
trolled by the Engine Control Module (ECM).A
cable and a vacuum controlled servo are not
used if the vehicle is equipped with a manual
transmission and a diesel engine. This is a ser-
vo-less system.The controls consist of two steering
wheel mounted switches. The switches are labeled:
ON/OFF, RES/ACCEL, SET, COAST, and CANCEL.
The system is designed to operate at speeds above
30 mph (50 km/h).
WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
OPERATION
When speed control is selected by depressing the
ON switch, the PCM (the ECM with a diesel engine)
allows a set speed to be stored in its RAM for speed
control. To store a set speed, depress the SET switch
while the vehicle is moving at a speed between 35
and 85 mph. In order for the speed control to engage,
the brakes cannot be applied, nor can the gear selec-
tor be indicating the transmission is in Park or Neu-
tral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
²Depressing the clutch pedal (if equipped).
NOTE: Depressing the OFF switch or turning off the
ignition switch will erase the set speed stored in
the PCM (the ECM with a diesel engine).
For added safety, the speed control system is pro-
grammed to disengage for any of the following condi-
tions:
²An indication of Park or Neutral
²A rapid increase rpm (indicates that the clutch
has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The speed signal increases at a rate of 10 mph
per second (indicates that the coefficient of friction
between the road surface and tires is extremely low)
²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the PCM (the ECM with
a diesel engine).
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
PCM (the ECM with a diesel engine) when the RES/
ACCEL is released. The PCM (the ECM with a diesel
engine) also has a9tap-up9feature in which vehicle
speed increases at a rate of approximately 2 mph for
each momentary switch activation of the RES/AC-
CEL switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - VACUUM SUPPLY
TEST
3.7L / 4.7L Gas Powered Engines
3.7L/4.7L gas powered engines: actual engine vac-
uum, a vacuum reservoir, a one-way check valve and
vacuum lines are used to supply vacuum to the speed
control servo.
(1) Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected
hose.
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury.
(3) If vacuum is less than ten inches of mercury,
determine source of leak. Check vacuum line to
engine for leaks. Also check actual engine intake
manifold vacuum. If manifold vacuum does not meet
this requirement, check for poor engine performance
and repair as necessary.
(4) If vacuum line to engine is not leaking, check
for leak at vacuum reservoir. To locate and gain
access to reservoir, refer to Vacuum Reservoir Remov-
al/Installation in this group. Disconnect vacuum line
at reservoir and connect a hand-operated vacuum
pump to reservoir fitting. Apply vacuum. Reservoir
vacuum should not bleed off. If vacuum is being lost,
replace reservoir.
8P - 2 SPEED CONTROLDR
SPEED CONTROL (Continued)