GMC 2004 Sierra 1500 Pickup Owner's Manual page 513

To release the spare tire from the secondary latch do
the following:
1. Check under the vehicle to see if the cable end is
visible.
2. If the cable is not visible proceed to Step 6.
If it is visible, first try to tighten the cable by turning
the wheel wrench clockwise until you hear two
clicks or feel it skip twice. You cannot overtighten
the cable.
3. Loosen the cable by turning the wrench
counterclockwise three or four turns.
4. Repeat this procedure at least two times. If the
spare tire lowers to the ground, continue with
Step 5 of "Removing the Spare Tire and Tools"
earlier in this section.
5. Turn the wrench counterclockwise until
approximately six inches (15 cm) of cable is
exposed.
7. Place the bottom edge of the jack on the wheel
blocks, separating them so that the jack is
balanced securely.
6. Stand the wheel blocks
on their shortest ends,
with the backs
facing each other.
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