1998 GMC Suburban Owner's Manual - Page 51

When you sit in a center seatingposition, you have a lap safety belt, which has no retractor. To make the belt longer, tilt the latchplate and pullit along the belt. To make the belt shorter, pull its freeend as shownuntil the belt issnug. Buckle, position and release it the same way as the lap part of a lap-shoulder belt.If the belt isn't long enough, see "Safety Belt Extender'' at the end of this section. Make surethe release button on the buckle is positioned so you would be able tounbuckle the safety belt quickly if you ever hadto. 1-39