1998 Chevrolet Express Van Owner's Manual - Page 126

Voltmeter When your engine is not running, but the ignition is on (in the RUN position), this gage shows your battery's state of charge in DC volts. Readings in the low warning zone may occur when a large number of electrical accessories are operating in the vehicle andthe engineis 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 higherengine speeds allow the charging system to create maximum power. You can only drive for ashort time with the reading in either warning zone. If you must drive, turn off all unnecessary accessories. Readings in either warning zone indicate a possible problem in theelectrical system. Have the vehicle serviced as soon as possible. 1 W VOLTS I When the engine is running, the gage shows the condition of the charging system. Readings between the low and high warningzones indicate the normal operating range. 2-55