GMC 2009 Sierra 1500 Crew Cab Owner's Manual page 63

2. If the child restraint manufacturer recommends that
the top tether be attached, attach and tighten the top
tether to the top tether anchor (loop), if your vehicle
has one. Refer to the child restraint instructions and
the following steps:
Example — Rear Driver's Side Position
Example — Rear Driver's Side Position
2.1. When using a child restraint with a top tether
in the rear driver side position:
A. Raise the headrest or head restraint.
B. Route the top tether (B) between
the headrest or head restraint posts,
through the loop (A), behind the inboard
headrest or head restraint post, and
under the center shoulder belt (C).
C. Attach the top tether (B) to the top
tether anchor (loop) (D) at the center
rear seating position.
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