GMC Hummer H3 2008 Owner's Handbook Manual page 33

Instrumentation and Controls
Charging System Light
This light should come on when
the ignition is on but the engine is
not running, as a check to show
you it is working properly.
If it doesn't come on, then have it
fixed so it will be ready to warn
you if there is a problem.
If it stays on or comes on while you
are driving, there may be a prob-
lem with this system.
Have it checked right away.
. . . 32
Driving while this light is on could
flatten your battery.
If there is a problem with the
battery charging system, a
message will be displayed. See
"Driver Information Centre
Messages" later in this section.
If you must drive a short distance
with the light on, turn off all your
accessories, such as the radio and
climate controls.
Brake System Warning Light
Your vehicle has "dual" brake
systems. If one system fails, the
other system can still stop your
vehicle.
This light should come on briefly
as you start your engine, as a check
to show you it is working properly.
If it doesn't come on, then have it
fixed so it will be ready to warn
you if there is a problem.