Pontiac 2005 Aztek Owner's Manual page 40

2. Attach the elastic cord to the comfort guide on the
center passenger shoulder belt.
1-34
3. Be sure that the belt is not twisted and it lies flat.
The guide must be on top of the belt.
4. Buckle, position and release the safety belt as
described in Center Rear Passenger Position
on page 1-28. Make sure that the shoulder belt
crosses the shoulder.
To remove and store the elastic cord, remove it from
the comfort guide. The elastic cord will go back
under the head restraint.