2012 GMC Sierra Owner's Manual - Page 464

10-78 Vehicle Care I. J. Jack Handle Extensions Spare Tire Lock (If equipped) 1. Open the spare tire lock cover on the bumper and use the ignition key to remove the spare tire lock (J). To remove the spare tire lock, insert the ignition key turn and pull straight out. 3. Insert the hoist end (open end) (F) of the extension through the hole (G) in the rear bumper. A. Spare Tire (Valve Stem Pointed Down) B. Hoist Assembly C. Hoist Cable D. Tire/Wheel Retainer E. Hoist Shaft F. Hoist End of Extension Tool G. Hoist Shaft Access Hole H. Wheel Wrench 2. Assemble the wheel wrench (H) and the two jack handle extensions (I), as shown. Do not use the chiseled end of the wheel wrench. Be sure the hoist end of the extension (F) connects to the hoist shaft. The ribbed square end of the extension is used to lower the spare tire. 4. Turn the wheel wrench counterclockwise to lower the spare tire to the ground. Continue to turn the wheel wrench until the spare tire can be pulled out from under the vehicle.