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Q: My battery light stays-on, on the dashboard why?

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I tried checking my alternator by pulling the battery head after starting the car the car idles perfectly and the light is still on. I switched on my headlights with the battery terminal disconnected from the battery and the car idles fine. Why is my battery light staying lighted 馃憜 on the dashboard? Thanks for your time!
My car has an automatic transmission.

You may have a failing voltage regulator that could be allowing the alternator to supply too much or too little amperage to the battery resulting in the battery never maintaining a consistent charge as it is designed to. The voltage regulator is a unit that regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. A common sign of this is usually the acid inside the battery boiling causing the battery to swell. You may also smell a bit of smoke due to things potentially getting too hot. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle鈥檚 charging system.

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