GMC 1998 Safari Owner's Manual page 143

Charging System Indicator Light
Voltmeter
4
--+I
The charging system light
will come on briefly when
you turn the ignition on, but
the engine is not running, as
a check to show you the
light is working.
Then it should go out once the engine is running. If it
stays on, or comes on while you are driving, you may
have a problem with the electrical charging system. It
could indicate that you have a loose accessory drive belt,
or another electrical problem. Have it checked right
away. Driving while this light is on could drain
your battery.
If you must drive
a
short distance with the light on, be
certain to turn off all your accessories, such as the radio
and heatedair conditioner.
.
When your engine is not
running, but the ignition is
on (in the RUN position),
the gage shows your
battery's state of charge in
DC volts.
When the ignition is running, the gage shows the
condition of the charging system. Readings between the
low and high warning zones indicate the normal
operating range.
Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system is not able to provide full power at
engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.
2-59