Front, Rear And Third Row Seat Belt TENSIONERS
Never use an ohmmeter or similar tool to test airbags, inflatable curtains or seat belt tensioners. Disconnect airbags or seat belt tensioners before testing them. Failure to do so may result in accidental deployment. This could result in serious injury or death.
There are up to seven seat belt tensioners in the car, two in the front, three on the rear seat and two on the third row if applicable. They contain an explosive charge which tensions the seat belts when deployed. The seat belt tensioners are separated from each other electrically. This means that each seat belt tensioner has a separate individual power supply and ground from the control module.
The front seat belt buckles are directly connected to the supplemental restraint system module (SRS). This means that data indicating whether the seat belts are engaged or not is transmitted directly to the supplemental restraint system module (SRS).
The seat belt tensioner tensions the seat belt to reduce the forward movement of the body. This also reduces the forces on the chest from the airbag and seat belt. Each seat has a seat belt tensioner.
The supplemental restraint system module (SRS) determines whether to deploy the seat belt tensioners based on whether the seat belts are being used. The seat belt tensioner will not be activated if the seat belt is not engaged. However, if the control module reads off incorrect data for the front seat belt buckles, the seat belt tensioners will be activated and the air bag will be deployed. Deployment of the airbags occurs in the same way as when the seat belts are not fastened.
The seat belt tensioner consists of a pyrotechnical charge and a cylinder with a piston. The piston is connected to a steel cable which is secured to the seat belt reel. When the control module activates the seat belt tensioner the piston is forced downwards by the expanding gas. The piston pulls in the steel cable which reels in the belt.
Never use an ohmmeter or similar tool to test airbags, inflatable curtains or seat belt tensioners. Disconnect airbags or seat belt tensioners before testing them. Failure to do so may result in accidental deployment. This could result in serious injury or death.