GMC Sierra Classic 2007 Owner's Manual page 565

1. Open the spare tire lock cover on the bumper
and use the ignition key to remove the lock, if
equipped with a spare tire lock (J). To
remove the spare tire lock, insert the key, turn
and pull straight out.
2. Assemble the wheel wrench (H) and the
two jack handle extensions (I) as shown.
Be sure the hoist end of the extension (F)
connects to the hoist shaft (E). The ribbed
square end of the extension is used to lower
the spare tire.
3. Insert the hoist end
(open end) (F) of the
extension through
the hole (G) in
the rear bumper.
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