1996 Chevrolet Tahoe Owner's Manual - Page 123

Voltmeter When your engine is not running, but the ignition is in the RUNposition, this gage showsyour battery's state of charge in DC volts. 9 19' Readings in thelow 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. You can only drive for short time with the reading in a either warning zone. If you must drive, turn off all unnecessary accessories. When the engine is running, the gage shows the condition of the charging system. Readings between the low and high warning zones indicate thenormal operating range. Readings in eitherwarning zone indicate a possible problem in the electrical system. Have the vehicle serviced as soon as possible. 2-60