1999 GMC Yukon Owner's Manual - Page 101

yellowblue Locking Rear Axle (If Equipped) If you have this feature, your locking rear axle can give you additional traction on snow, mud, ice, sand or gravel. It works like a standard axle most of the time, but when one of the rear wheels has no traction and the other does, this feature will allow the wheel with traction to move the vehicle. Power Windows (If Equipped) Windows Manual Windows To open your manual windows, turn the hand crank on each door to raise or lower your side door windows. 2-Door Utility 2-31