GMC 2009 Sierra - Manual (Page 32)

{ CAUTION:
A safety belt that is not properly worn may not
provide the protection needed in a crash. The
person wearing the belt could be seriously
injured. The shoulder belt should go over the
shoulder and across the chest. These parts of
the body are best able to take belt restraining
forces.
4. Buckle, position, and release the safety belt as
described previously in this section. Make sure
that the shoulder belt crosses the shoulder.
To remove and store the comfort guide, squeeze the
belt edges together so that you can take them out of the
guides. Slide the guide onto the storage clip.
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