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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 446 (Supplemental Inflatable Restraint System) >> Description and Operation >> SIR System Description and Operation >> Seat Belt Pretensioners (Buckle)

Seat Belt Pretensioners (Buckle)

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The seat belt pretensioners (driver and passenger) consist of a housing, seat belt buckle (pretensioner), seat belt webbing, an initiator, and a canister of gas generating materials. To view the locations of the seat belt pretentioners refer to SIR Identification Views . The initiator is part of the seat belt pretensioner deployment loop. When the vehicle is involved in a collision of sufficient force, the SDM causes current to flow through the seat belt deployment loops to the initiator. Current passing through the initiator ignites the material in the canister producing a rapid generation of gas. The gas produced from this reaction deploys the seat belt pretensioners which removes all of the slack in the seat belts. Depending on the severity of the collision, the seat belt pretensioners may deploy without the front air bags deploying, or they will deploy immediately before the front air bags deploy. A shorting bar (if equipped) is located in the connector.