deployment. A growlin g or grin ding sound while
attem pt ing to oper ate the seat belt ret ract or is a sure
indication that the sea t belt tensioner h as been
deployed an d requires repla cement. (Refer to 8 -
ELECTRICAL/RESTRAINTS/FRONT SEAT BELT &
RETRACTOR - RE MOVAL).
OPERATION
The seat belt t ension ers ar e deployed in conjun c-
tion with the airbags by a signal gen erated by th e
Airba g Control Module (ACM) th rough the dr iver and
pa ssen ger sea t belt tensioner line 1 and lin e 2 (or
squib) circuits (Fig. 39). When the ACM sends the
pr oper elect rical signal to the tensioners, the electri-
cal ener gy generates enough heat to init iat e a small
pyrotech nic gas generator. The gas generator is
insta lled so th at it directs its expelled gas a t the
underside of th e piston in the cylinder. The piston is
connect ed to a cable that is wound aroun d a pu lley
on one end of the retractor spool. As the ga s expa nds,
it propels the piston through th e t ube, which pulls
the ca ble an d r otates t he ret ract or spool to take u p
slack in the seat belt webbing.
Once a seat belt ten sioning sequence has been
complet ed, t he forwa rd mom entu m of t he occupan t
results in deformation of th e torsion bar. Removing
excess sla ck fr om the fr ont seat belts n ot only keeps
the occupants properly positioned for an airbag
deployment following a front al impact of t he vehicle,
but also h elps to redu ce injuries tha t t he occupan t
might otherwise exper ience in a fr ontal impact event
as a r esu lt of ha rmful con tact with the steering
wheel, steerin g colu mn, instrument panel a nd/or
windshield. The torsion bar is designed to deform in
order to cont rol the loa ds being a pplied to the occu-
pa nt by the seat belt dur ing a frontal impact, furt her
reducing the pot ential for occupant injuries.
The ACM monitors the condition of the seat belt
tensioners through circuit resistance. The ACM will
illuminate t he airbag indica tor in th e ElectroMe-
chanical Inst rument Cluster (EMIC) and store a
Diagnostic Trouble Code (DTC) for any fau lt that is
detected. F or pr oper diagnosis of the sea t belt ten-
sioner s, a diagn ost ic scan tool is required. Refer to
the a ppr opr iate diagnostic informat ion.
SEAT BELT T U RN I N G LOOP
ADJ U ST ER
REMOVAL
WARNING: To avoid personal injury or death, on
vehicles equipped with airbags, disable the supple-
mental restraint system before attempting any
steering wheel, steering column, airbag, seat belt
tensioner, or instrument panel component diagno-
sis or service. Disconnect and isolate the battery
negative (ground) cable, then wait two minutes for
the system capacitor to discharge before perform-
ing further diagnosis or service. This is the only
sure way to disable the supplemental restraint sys-
tem. Failure to take the proper precautions could
result in accidental airbag deployment.
WARNING: To avoid personal injury or death, during
and following any seat belt service, carefully
inspect all seat belts, buckles, mounting hardware,
retractors, and anchors for proper installation, oper-
ation, 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. Never attempt to repair a seat
belt component. Always replace damaged or faulty
seat belt components with the correct, new and
unused replacement parts listed in the
DaimlerChrysler Mopar Parts Catalog.
(1) Move the fron t seat to its most for ward posit ion
for easiest a ccess t o the B-pillar trim.
Fig. 39 Seat Belt Tensioner Operation
1 - TUBE
2 - PISTON
3 - CABLE
4 - CYLINDER
VA RESTRAINTS 8O - 33
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