Red Seal Automotive Service Technician Practice Exam

Which of the following is a common sign of a failing alternator?

1. Steering wheel vibrations

2. Dimmed headlights and battery warning light

3. Excessive exhaust fumes

4. Engine misfiring

The correct answer is: Dimmed headlights and battery warning light

A common sign of a failing alternator includes dimmed headlights and the illumination of the battery warning light on the dashboard. The alternator's function is to charge the battery while the engine is running and power the electrical systems of the vehicle. When it starts to fail, it can no longer provide adequate voltage to keep the battery charged properly. As a result, you may notice that the headlights become dimmer, especially when other electrical components are used, such as the air conditioning or radio. The battery warning light serves as an alert from the vehicle's onboard computer that there is an issue with the charging system, which often points to alternator problems. Other options, while they may suggest different issues, do not directly relate to alternator failure. Steering wheel vibrations are typically associated with problems in the steering or suspension components. Excessive exhaust fumes are generally linked to issues with the fuel system or exhaust system rather than the electrical components. Engine misfiring can result from a range of factors, such as spark plug issues or fuel delivery problems, but it is not a typical symptom of alternator failure. Thus, the presence of dimmed headlights and the battery warning light is a clear indicator of problems originating from the alternator.