GMC 2009 Sierra - Manual (Page 403)

Secondary Latch System
Your vehicle has an underbody-mounted tire hoist
assembly equipped with a secondary latch system.
It is designed to stop the spare tire from suddenly falling
off your vehicle. For the secondary latch to work, the
spare must be installed with the valve stem pointing
down. See Storing a Flat or Spare Tire and Tools
on page 5-94.
{ CAUTION:
Before beginning this procedure read all the
instructions. Failure to read and follow the
instructions could damage the hoist assembly
and you and others could get hurt. Read and
follow the instructions listed next.
To release the spare tire from the secondary latch:
1. Check under the
vehicle to see if the
cable end is visible.
If the cable is not
visible proceed
to Step 6.
2. 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
on page 5-82.
5-91