2004 GMC Sierra 1500 Pickup Owner's Manual - Page 80

Dual Stage Air Bags If your vehicle has frontal air bags with dual stage deployment, the amount of restraint will adjust according to crash severity. For moderate frontal impacts, these air bags inflate at a level less than full deployment. For more severe frontal impacts, full deployment occurs. If the front of your vehicle goes straight into a wall that does not move or deform, the threshold level for the reduced deployment is about 10 to 16 mph (16 to 25 km/h), and the threshold level for a full deployment is about 20 to 25 mph (32 to 40 km/h). The threshold level can vary, however, with specific vehicle design, so that it can be somewhat above or below this range. If your vehicle strikes something that will move or deform, such as a parked car, the threshold level will be higher. The air bag is not designed to inflate in rollovers, rear impacts, or in many side impacts because inflation would not help the occupant. Single Stage Air Bags If your vehicle has frontal air bags with single stage deployment and your vehicle goes straight into a wall that does not move or deform, the threshold level is about 13 to 16 mph (20 to 25 km/h). The threshold level can vary, however, with specific vehicle design, so that it can be somewhat above or below this range. If your vehicle strikes something that will move or deform, such as a parked car, the threshold level will be higher. The air bag is not designed to inflate in rollovers, rear impacts, or in many side impacts because inflation would not help the occupant. What Makes an Air Bag Inflate? In an impact of sufficient severity, the air bag sensing system detects that the vehicle is in a crash. The sensing system triggers a release of gas from the inflator, which inflates the air bag. The inflator, air bag, and related hardware are all part of the air bag modules inside the steering wheel and in the instrument panel in front of the right front passenger. Seat Position Sensors Vehicle's with dual stage air bags are also equipped with special sensors which enable the sensing system to monitor the position of both the driver and passenger front seats. The seat position sensor provides information which is used to determine if the air bags should deploy at a reduced level or at full deployment. 1-74