Voltmeter

The voltmeter is an instrument that shows the voltage of the vehicle electrical system. The voltmeter indicates the ability of the charging system to keep the storage battery charged. The voltmeter is wired in parallel with other circuits in the vehicle.

When the engine is running the voltmeter indicates charging system voltage. If the engine is not running and the ignition switch is in the RUN or START position the voltmeter will show battery voltage. The voltmeter can be used as a first step in diagnosing many electrical problems. Battery voltage drop can be seen while the engine is cranking. After the engine is running, generator output voltage is indicated.

The voltmeter should read between 11-13 volts during extended idle or just after starting. As the electrical load is increased, or in stop-and-go driving, the pointer may rotate temporarily to the bottom of the scale. A voltmeter reading continuously below 11 volts or above 16 volts indicates an electrical system problem.