GMC 2001 Savana Van Owner's Manual page 238

1. Check the other vehicle. It must have a 12
battery with a negative ground system.
NOTICE:
If the other system isn't a 12
negative ground, both vehicles can be damaged.
If you have a diesel engine vehicle with two batteries
(or more) you should know before you begin that,
especially in cold weather, you may not be able to
get enough power from a single battery in another
vehicle to start your diesel engine.
If your vehicle has more than one battery, use the
battery that is under the hood of the vehicle. This
will reduce the electrical resistance.
5-4
-
volt
-
volt system with a
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) and a manual transmission
in NEUTRAL.
3. Turn off the ignition on both vehicles. Turn off all
lamps that aren't needed, and radios. This will avoid
sparks and help save both batteries, and could save
your radio.