Buick 2008 Lucerne Owner's Manual page 318

CAUTION:
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Using a match near a battery can cause battery
gas to explode. People have been hurt doing
this, and some have been blinded. Use a
flashlight if you need more light.
Be sure the battery has enough water. You do
not need to add water to the battery installed
in your new vehicle. But if a battery has filler
caps, be sure the right amount of fluid is there.
If it is low, add water to take care of that first.
If you do not, explosive gas could be present.
Battery fluid contains acid that can burn you.
Do not get it on you. If you accidentally get it
in your eyes or on your skin, flush the place
with water and get medical help immediately.
5-50
CAUTION:
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Fans or other moving engine parts can injure
you badly. Keep your hands away from moving
parts once the engine is running.
5. Check that the jumper cables do not have loose or
missing insulation. If they do, you could get a
shock. The vehicles could be damaged too.
Before you connect the cables, here are some
basic things you should know. Positive (+) will go to
positive (+) or to a remote positive (+) terminal if
the vehicle has one. Negative (−) will go to a heavy,
unpainted metal engine part or to a remote
negative (−) terminal if the vehicle has one.
Do not connect positive (+) to negative (−) or you
will get a short that would damage the battery
and maybe other parts too. And do not connect the
negative (−) cable to the negative (−) terminal on
the dead battery because this can cause sparks.