1998 GMC Suburban Owner's Manual - Page 17

A C But don't havea seatback reclined your vehicleis moving. if Sitting in a reclined position when your vehicle is in motion can be dangerous. Even if you buckle up, your safety beltscan't do their jobwhen you're reclined like this, The shoulderbelt can't do itsjob because it won't be against your body. Instead, it will be in front of you. In a crash you could go into it, receiving neckor other injuries. The lapbelt can't do its job either. In a crash the belt could go up over your abdomen. The belt forces would be there, not at your pelvic bones. This could causeserious internal injuries. For proper protection when the vehicle is in motion, have the seatback upright. Then sit well back in the seat and wear your safety belt properly. Head Restraints Slide thehead restraint up or down so that the top of the restraint is closest to the top of your ears. Thisposition reduces the chance of a neck injury in a crash. 1-5