Jeep 2011 Grand Cherokee - Owner Manual - Manual (Page 94)

To attach a child restraint tether strap:
For rearward facing infant seats secured in the center seat
position with the vehicle seat belts, the rear center seat
position has an armrest tether that secures the arm rest in
the upward position. To access the center seat arm rest
tether first lower the arm rest. The tether is located
behind the armrest and hooked onto the plastic seat
backing.
Pull down on the tether to unhook it from the plastic seat
backing, then raise the armrest and attach the tether hook
to the strap located on the front of the arm rest.
Center Seat Position Arm Rest Tether
92 THINGS TO KNOW BEFORE STARTING YOUR VEHICLE