2007 GMC Savana Van Owner's Manual - Page 76

5. Pull the rest of the shoulder belt all the way out of the retractor to set the lock. 6. To tighten the belt, push down on the child restraint, pull the shoulder belt to tighten the lap belt portion and feed the shoulder belt back into the retractor. If you are using a forward-facing child restraint, you may find it helpful to use your knee to push down on the child restraint as you tighten the belt. You should not be able to pull more of the belt out of the retractor once the lock has been set. 76