1999 GMC Jimmy Owner's Manual - Page 39
1999 GMC Jimmy Manual
Page 39 highlights
yellowblue When the shoulder belt is pulled out all the way, it will lock. If it does, let it go back all the way and start again. If the belt is not long enough, see "Safety Belt Extender" at the end of this section. Make sure the release button on the buckle is positioned so you would be able to unbuckle the safety belt quickly if you ever had to. 3. To make the lap part tight, pull down on the buckle end of the belt as you pull up on the shoulder part. 1-33