Savaria Toyota Sienna Owner's Manual page 36

3. Once the bench is lowered all the way, ensure the lock lever is
engaged by attempting to pivot the bench back up. If it moves up
without locking, push the bench back down with more force and
try lifting it again. If difficulty arises, contact Savaria® Vehicle Group
4. Raise the backrest by pressing the red lever located at the rear of
the bench on the driver's side and lifting it into position.
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