GMC 2004 Savana Van Owner's Manual page 66

There is no top strap anchor in the center seat position
of the second row. Do not secure a child seat in this
position if a national or local law requires that the
top strap be anchored, or if the instructions that come
with the child restraint say that the top strap must
be anchored.
If your child restraint does not have the LATCH system,
you'll be using a lap-shoulder belt which works the
same way as the safety belts in the rear outside seat
positions. To learn how to secure a child restraint with a
lap-shoulder belt, refer to the instructions in Securing
a Child Restraint in a Rear Outside Seat Position
on page 1-57.
1-60
Securing a Child Restraint in a
Center Seat Position (3rd, 4th and
5th Row)
If your child restraint is equipped with the LATCH
system, see Lower Anchorages and Top Tethers for
Children (LATCH System) on page 1-52. See Top Strap
on page 1-49 if the child restraint has one.
For vehicles with a fourth or fifth row four-passenger
bench seat, there are no top strap anchors in the center
seating positions of a fourth or fifth row four-passenger
bench seat. Do not secure a child seat in these positions
if a national or local law requires that the top strap
must be anchored.