GMC 2006 Sierra - Manual (Page 14)

Seatback Latches
The front seatbacks fold forward to allow access to the
rear of the cab.
To fold the seatback forward, lift the lever located on
the outboard side of the seat cushion.
{ 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.
To return the seatback to the upright position, push the
seatback rearward until it latches. After returning the
seatback to its upright position, push and pull on
the seatback to make sure it is locked.
Rear Seats
Rear Seat Operation (Extended Cab)
Folding the Rear Seat
The rear seat in the extended cab can be folded up to
provide more cargo space.
To fold the seat up, do the following:
1. Push down on the front
of the seat cushion
while pulling down on
the release strap
which is located under
the seat cushion.
2. Pull the seat cushion up until it latches with the
seatback.
3. After latching the seat cushion up, pull forward on it
to make sure it is locked.
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