1999 GMC Sonoma Owner's Manual - Page 37
1999 GMC Sonoma Manual
Page 37 highlights
yellowblue Center Passenger Position Lap Belt If your vehicle has a bench seat, someone can sit in the center position. When you sit in a center seating position, you have a lap safety belt, which has no retractor. To make the belt longer, tilt the latch plate and pull it along the belt. 1-31