Dodge Ram Truck 1500-2500-3500. Manual - part 571
SEAT BELT TENSION REDUCER
DESCRIPTION
A seat belt tension reducer (5) is standard equipment
for the driver side front outboard seat belt on standard
cab versions of this model. The tension reducer is
integral to the driver side front outboard seat belt and
retractor unit, which is secured to the inner B-pillar on
the left side of the vehicle. The retractor is concealed
beneath the molded plastic inner B-pillar trim.
The seat belt tension reducer consists primarily of a
12-volt Direct Current (DC) solenoid and an integral
connector receptacle (6) that is located on the forward
facing end housing of the retractor. The seat belt ten-
sion reducer is controlled by a battery current output
of the ignition switch and a ground path provided by
the seat belt switch, and is connected to the vehicle
electrical system through a dedicated take out of the
body wire harness by a keyed and latching molded
plastic
connector
insulator
to
ensure
a
secure
connection.
The seat belt tension reducer cannot be repaired and, if faulty or damaged, the entire driver side front outboard seat
belt and retractor unit must be replaced. (Refer to 8 - ELECTRICAL/RESTRAINTS/FRONT OUTBOARD SEAT BELT
& RETRACTOR - REMOVAL).
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 current 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 igni-
tion 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
webbing 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 desirable 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 conven-
tional 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 con-
nector 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 system 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 negative
(ground) cable, then wait two minutes for the system capacitor to discharge before performing further diag-
nosis or service. This is the only sure way to disable the supplemental restraint system. Failure to take the
proper precautions could result in accidental airbag deployment.
8O - 318
RESTRAINTS - SERVICE INFORMATION
DR/DH