GMC Sierra Owner's Manual page 88

Rear Passenger Side Position
Rear Passenger Side Position
2.2. For a top tether in the rear
passenger side position:
2.2.1. Remove the passenger side
head restraint and center
headrest. See Head
Restraint or Headrest
Removal and Reinstallation
later in this section.
2.2.2. Route the top tether (3)
through the loop (2).
2.2.3. Attach the top tether (3) to
the passenger side of the
center top tether metal
anchor (1).
2.2.4. Make sure the child restraint
top tether hook is
completely closed and
secured to the top tether
anchor.
Seats and Restraints
Rear Center Position
Rear Center Position
87