GMC 2015 Sierra Owner's Manual page 456

8. Do not let the other end touch
metal. Connect it to the
positive (+) terminal of the good
battery. Use a remote
positive (+) terminal if the
vehicle has one.
9. Connect the black negative ( )
cable to the negative ( ) terminal
of the good battery. Use a
remote negative ( ) terminal if
the vehicle has one.
Do not let the other end touch
anything until the next step.
10. Connect the other end of the
negative ( ) cable.
4.3L Shown, 5.3L and 6.2L Similar
To the metal bracket that is
bolted to the engine and
supports the resonator, on
the vehicle with the dead
battery.
Vehicle Care 10-93
6.0L
To the generator bracket, on
the vehicle with the dead
battery.