Chevrolet 2008 Avalanche Owner's Manual page 52

Lower Anchor and Top Tether Anchor
Locations
Rear Seat
The right side rear passenger and center seating
positions have exposed metal anchors located in the
crease between the seatback and the seat cushion.
1-48
i
(Top Tether Anchor):
Seating positions with top
tether anchors.
j
(Lower Anchor):
Seating positions with
two lower anchors.
To assist you in locating
the top tether anchors, the
top tether anchor symbol
is located near the top
tether anchors.