GMC 2015 Sierra Owner's Manual page 113

3-54 Seats and Restraints
3. For forward-facing child
restraints, attach and tighten the
top tether to the top tether
anchor (loop). Follow the child
restraint instructions, the vehicle
LATCH anchor weight limits
described at the beginning of
this section, and the following
steps:
Example Rear Driver Side
Position
Example Rear Driver Side
Position
3.1. For a top tether in the rear
driver side position:
3.1.1. Remove the
headrest.
3.1.2. Route the top
tether (4) through the
loop (3) on the driver
side under the
center shoulder
belt (2).
3.1.3. Then attach the top
tether (4) to the top
tether
anchor (loop) (1) at
the center rear
seating position.
3.2. For a top tether in the rear
center position:
3.2.1. Route the top
tether (4) through the
center loop (1), and
behind the
passenger side
headrest post.
3.2.2. Then attach the top
tether (4) to the top
tether anchor (loop)
at the rear
passenger side
seating position.
3.3. For a top tether in the rear
passenger position:
3.3.1. Remove the
headrest.