Pontiac G5 2010 Owner's Manual page 40

To raise the rear seatback, lift it up and push rearward
until you hear a click. Push and pull on the seatback
to be sure it is locked into place.
WARNING:
{
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
pull forward on the top of the seatback at the area
of the latch to be sure it is locked.
2-10
WARNING:
{
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.