What are the signs of a failing alternator?

A failing alternator typically presents specific signs that indicate it is no longer effectively charging the battery or providing sufficient electrical power to the vehicle's components. Dimming headlights are a common first indication; they may flicker or become noticeably less bright, particularly at idle when the engine is under less load. Additionally, if the alternator is failing, the battery may not receive a consistent charge, leading to it dying or being unable to start the vehicle.

Furthermore, warning lights on the dashboard, particularly the battery warning light, indicate that the charging system is compromised. This is a direct result of insufficient voltage reaching the battery due to the alternator's failure.

These symptoms directly relate to the alternator's functionality and electrical output, distinguishing them from issues associated with other vehicle components, which might be reflected in the other choices. Increased fuel consumption and engine noise could pertain to various engine or fuel system issues, frequent oil changes indicate maintenance or lubrication problems, and overheating engines with coolant leaks suggest cooling system failures rather than electrical system problems.