Chevrolet 2006 TrailBlazer EXT Owner's Manual page 32

2. Push the latch plate into the buckle until it clicks.
Pull up on the latch plate to make sure it is secure.
When the shoulder belt is pulled out all the way,
it will lock. If it does, let it go back all the way and
start again.
If the belt is not long enough, see Safety Belt
Extender on page 1-31.
Make sure the release button on the buckle is
positioned so you would be able to unbuckle the
safety belt quickly if you ever had to.
3. To make the lap part tight, pull up on the
shoulder part.
1-26
The lap part of the belt should be worn low and snug on
the hips, just touching the thighs. In a crash, this applies
force to the strong pelvic bones. And you would be
less likely to slide under the lap belt. If you slid under it,
the belt would apply force at your abdomen. This could
cause serious or even fatal injuries. 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.