Sprinter 2500 L5-2.7L DSL Turbo (2003)
Seat Belt Tensioner: Description and Operation
Seat Belt Tensioner
Front seating position seat belt tensioners supplement the standard driver and optional passenger air-bags for all versions of this model. When equipped,
the seat belt tensioner is integral to the front seat belt and retractor units, which are secured to the inner B-pillars of the vehicle. Each retractor is
concealed beneath the molded plastic B-pillar trim. The seat belt tensioner consists primarily of a tubular steel housing, a piston, a cable, a torsion bar,
and a small pyrotechnically activated gas generator. All of these components are located on one side of the retractor spool on the outside of the retractor
housing except for the torsion bar, which serves as the spindle upon which the retractor spool rotates. The seat belt tensioner is controlled by the Airbag
Control Module (ACM) and is connected to the vehicle electrical system through a dedicated take out of the vehicle wire harness by a keyed, snap-fit
molded plastic connector insulator to ensure a secure connection.
The seat belt tensioner cannot be repaired and, if faulty or damaged, the entire front seat belt and retractor unit must be replaced. If the front airbags have
been deployed, the seat belt tensioners have also been deployed. The seat belt tensioner is not intended for reuse and must be replaced following a
deployment. A growling or grinding sound while attempting to operate the seat belt retractor is a sure indication that the seat belt tensioner has been
deployed and requires replacement.
