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Q: Car dies when lights go on. New battery new alternator.

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Car stalls when lights are being turned on. New battery new alternator. Battery voltage goes down.
My car's transmission is unknown to me.

Hi There, It sounds like you may have a voltage maintenance problem. This is usually caused by a faulty voltage regulator. 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. 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. In some cases when a battery is too weak or damaged, it may no longer hold a charge for any length of time, in which case the alternator may be doing its job, but the battery is just simply too weak to hold a charge. In either case, I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.

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