Charger V8-5.7L VIN H (2007)
Seat Belt Tensioner: Description and Operation
Operation
OPERATION
The seat belt tensioners are deployed in conjunction with the front airbags by a signal generated by the Occupant Restraint Controller (ORC) through the
driver or passenger seat belt tensioner line 1 and line 2 (or squib) circuits. When the ORC sends the proper electrical signal to the tensioners, the
electrical energy generates enough heat to initiate a small pyrotechnic gas generator. The gas generator is installed in one end of a steel tube that contains
numerous steel balls. As the gas expands, it pushes the steel balls through the tube into a cast metal housing, where a ball guide directs the balls into
engagement with the teeth of a sprocket that is geared to one end of the retractor spool. As the balls drive past the sprocket, the sprocket turns and drives
the seat belt retractor spool causing the slack to be removed from the front seat belts. The ball trap captures the balls as they leave the sprocket and are
expelled from the housing.
Removing excess slack from the front seat belts not only keeps the occupants properly positioned for an airbag deployment following a frontal impact of
the vehicle, but also helps to reduce injuries that the occupant might experience in these situations as a result of harmful contact with the steering wheel,
steering column, instrument panel and/or windshield. Also, the seat belt tensioner torsion bar that the retractor spool rides upon is designed to deform in
order to control the loading being applied to the occupants by the seat belts during a frontal impact, further reducing the potential for occupant injuries.
The ORC monitors the condition of the seat belt tensioners through circuit resistance, and will illuminate the airbag indicator in the instrument cluster
and store a Diagnostic Trouble Code (DTC) for any fault that is detected. For proper diagnosis of the seat belt tensioners, a scan tool is required and the
appropriate body diagnostic information.
