GMC 2006 Envoy Owner's Manual page 402

Notice: If the jumper cables are connected or
removed in the wrong order, electrical shorting may
occur and damage the vehicle. The repairs would
not be covered by your warranty. Always connect
and remove the jumper cables in the correct
order, making sure that the cables do not touch
each other or other metal.
Jumper Cable Removal
A. Heavy, Unpainted Metal Engine Part or Remote
Negative ( ) Terminal
B. Good Battery or Remote Positive (+) and Remote
Negative ( ) Terminals
C. Dead Battery or Remote Positive (+) Terminal
5-46
To disconnect the jumper cables from both vehicles, do
the following:
1. Disconnect the black negative ( ) cable from the
vehicle that had the dead battery.
2. Disconnect the black negative ( ) cable from the
vehicle with the good battery.
3. Disconnect the red positive (+) cable from the
vehicle with the good battery.
4. Disconnect the red positive (+) cable from the
other vehicle.