GMC 2007 Sierra - Manual (Page 21)

To return the seat to the normal seating position,
do the following:
1. Lift the seatback up and push it rearward all
the way.
{ CAUTION:
If the seatback is not locked, it could
move forward in a sudden stop or crash.
That could cause injury to the person
sitting there. Always push and pull on the
seatback to be sure it is locked.
2. Push and pull on the seatback to make sure it
is locked into place.
3. Lower the seat cushion until it latches into
position. Pull up on the cushion to make
sure it is locked into place.
{ CAUTION:
A safety belt that is improperly routed, not
properly attached, or twisted will not
provide the protection needed in a crash.
The person wearing the belt could be
seriously injured. After raising the rear
seatback, always check to be sure that the
safety belts are properly routed and
attached, and are not twisted.
Make sure that the safety belt buckles on the
driver’s side seatback are accessible to the
outboard and center occupant and are not under
the seat cushions.
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