2003 GMC Sierra 1500 Pickup Owner's Manual - Page 55

With this system, use the LATCH system instead of the vehicle's safety belts to secure a child restraint. If a LATCH-type child restraintisn't attached to its anchorage points, the restraint won't be able to protect a child sitting there. In a crash, the child could be seriously injured or killed. Make sure that a LATCH-type child restraint is properly installed using the anchorage points, or use the vehicle's safety belts to secure the restraint. See "Securing a Child Restraint Designed for the LATCH System", "Securing a Child Restraint in the Center Front Seat Position", "Securing a Child Restraint in the Right Front Seat Position" or "Securing a Child Restraint in aCenter Rear Seat Position" in the a Index for information on how to secure child restraint in your vehicle. 1-48