Before servicing the front seat belt and retractor unit in a four-door vehicle, first disconnect and isolate the battery negative cable to shut down the supplemental restraint system and then wait two minutes for its capacitor to discharge. Check every belt, buckle, bracket, retraction system, strap and anchor to make sure they are installed right and if you notice any frayed or cut seal, change that belt. In case the seat belt tensioner fails to deploy, go with the advised procedures for non-deployed supplemental restraints; if it deploys, use the directions specified once a seat belt tensioner deploys. Pull the front seat as far forward as it will go to reach the lower anchor and the trim on the B-pillar easily. Take out the screw holding the lower anchor to the outboard front seat frame, unsnap and throw out the trim cover from the belt loop on the front seat and remove the screw holding the loop to the height adjuster on the upper B-pillar. After that, remove the seat belt turning loop from the seat height adjuster, take the lower trim off the inside part of the B-pillar and slide the seat belt webbing through the slot in the B-pillar lower trim. Disconnect the yellow wire from the tensioner initiator at the seat belt retractor, unscrew the lower retractor bracket from the B-pillar and remove both seat belt and retractor as one piece.