Hummer 2008 H2 Owner's Manual page 422

Removing the Jack (SUV)
The jack is stored in the rear cargo area on the
driver side.
1. To access the jack pull on the two latches to
remove the trim cover.
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2. Insert the wheel wrench into the hole and turn it
counterclockwise to release it.
3. Grasp and lift the jack out of the bracket.