GM Service Manual Online
For 1990-2009 cars only

Object Number: 868139  Size: A2

When the engine is not running, but the ignition is in RUN, this gage shows your battery's state of charge in DC volts.

While the engine is running, this gage shows the condition of the charging system. The gage may transition from a higher to lower or a lower to higher reading. This is normal. Readings between the low and high warning zones indicate the normal operating range. The voltmeter gage may also read lower when in fuel economy mode. This is normal.

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.

You can only drive for a short 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 the electrical system. Have the vehicle serviced as soon as possible.

Readings in either red warning zone indicate a possible problem in the electrical system. When the engine is not running, but the ignition is in RUN, this gage shows the 24-volt battery's state of charge. When the engine is running, the gage shows the condition of the 24-volt charging system. 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 may not be able to provide full power at engine idle. As engine speeds are increased, this condition should correct itself because higher engine speeds allow the charging system to create maximum power.

The 24-voltmeter gage is located in the lower right side of the accessory panel.

Voltmeter Gage Operation

Engine Running


Object Number: 1613263  Size: A1

The gage needle should be in the green band when engine speed is above an idle. If the needle is not in the green band, the fuse element may have melted. If the fuse is not open and the system still does not operate properly, consult your GM Goodwrench® dealer.

Engine Off


Object Number: 1613265  Size: A1

In a no load situation, with the engine off, the gage needle should be mid-way between the red band and green band, in the yellow band. If the gage needle is in the lower end of the yellow band, this is unacceptable, and the 24 volt battery may have run down.