1996 Toyota T100 DLX 6 Cyl 3.4L
Why does my battery voltage gauge fluctuate when I turn on heater, blinkers? Had battery and alternator checked. Ok
Spoon Sports 1/4/2012
The battery in your car does not constantly charge while driving. Electricity is needed to run the headlights, starter, radio, etc. In order to save wear on the alternator/generator, the battery is sometimes used to power these electrical devices as your car's internal sensors see fit. When the battery's charge drops below a certain voltage, the alternator kicks in again to keep the battery at its optimum level.