GMC 2013 Yukon XL Denali Owner's Manual page 374

J. Hoist End of Extension Tool
K. Spare Tire Lock
1. To reach the hoist shaft access
cover (C), you will first need to
remove the hitch cover. Remove
it by turning the two fasteners
located at the bottom of the
cover counterclockwise and then
pull the cover down and rotate
towards you.
2. Remove the hoist shaft access
cover (C) on the bumper to
access the spare tire lock (K).
3. To remove the spare tire lock,
insert the ignition key, turn it
clockwise and then pull
straight back.
4. Assemble the two jack handle
extensions (D) and wheel
wrench (E) as shown.
5. Insert the open end of the
extension (J) through the hole in
the rear bumper (I) (hoist shaft
access hole).
Be sure the hoist end (J) of the
extension (D) connects to the
hoist shaft (B). The ribbed
square end of the extension is
used to lower the spare tire.