GMC 2003 C4C042 Owner's Manual page 233

9. Connect the other end of the negative (
least 18 inches (45 cm) away from the dead battery,
but not near engine parts that move. The electrical
connection is just as good there, and the chance of
sparks getting back to the battery is much less.
5-8
10. Now start the vehicle with the good battery and run
the engine for one or two minutes. If your vehicle
has the high idle option, use it.
11. Try to start the vehicle with the dead battery.
If it won't start after a few tries, it probably
needs service.
NOTICE:
Damage to your vehicle may result from
electrical shorting if jumper cables are removed
incorrectly. To prevent electrical shorting, take
care that they don't touch each other or any
-
) cable at
other metal. The repairs wouldn't be covered by
your warranty.