Q: Voltage drop noticed during night driving. The headlights dim and then return to normal.

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While driving at night notice headlight dim low and brighten up. Voltage shows drop for a second. Bad ground?

My car has 105000 miles.
My car has an automatic transmission.

This may be a sign of a failing voltage regulator or potentially a bad ground connection. As you may know, the voltage regulator regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this will result in the alternator allowing too much power to be delivered to the battery, damaging the wires and prematurely destroying the battery.

In other cases, it may result in the alternator not supplying enough power to the battery, causing the battery to be undercharged or not charged at all. In either case, I would recommend having an expert, such as one from YourMechanic, come to your location to diagnose your vehicle’s charging system and suggest the needed repairs.

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