What are the symptoms of a failing alternator?

Wednesday 4th September 2024



The alternator plays a crucial role in keeping your vehicle's electronics running. From failing to charge your car’s battery to being unable to use the radio or windshield wipers, a faulty alternator can disrupt your driving experience. Formula One Autocentres details the signs of a failing alternator.  

Dead car battery 

When you turn the ignition on, you notice your car fails to spark into life. It could either be down to a dead battery or a failing alternator.  

While you may assume that you need a new battery, a faulty alternator may be to blame as it will fail to charge the battery while driving. To know whether the battery or alternator is the issue, jump-start the vehicle with jump leads and remove them quickly. If your car jump starts with the cables and continues to run, then the battery needs replacing. However, if your vehicle starts and dies after disconnecting the cables, then there is an issue with the alternator. 

If the alternator is faulty, we recommend replacing it immediately. 

The headlights flicker, dim or are too bright 

A symptom of a failing alternator is the headlights dimming or flickering while driving. One reason is that the alternator struggles to generate enough power to keep your headlights running. The headlights may be too bright, flicker or appear dimmer than usual. We recommend booking a full service immediately if you notice any issues with the alternator or headlights. Our trained specialists can replace your alternator or headlight bulbs with new ones. 

Your car frequently stalls 

Do you notice the engine struggling when you start your car? You’ll hear a clicking sound, instead of the engine. However, if you are driving and the battery light activates on the dashboard, the engine control unit is not getting enough power from the alternator to keep your car running.  

The warning light activates on the dashboard 

Most vehicles have a battery-shaped warning light on the dashboard. If your car fails to start, it could signal a failed alternator. The typical voltage for an alternator is about 13 to 14.5 volts. Also, it depends on whether you use other accessories, such as the radio and wipers since your vehicle needs more power to keep them running. A faulty alternator won’t be able to keep all your accessories running. 

Knowing the symptoms of a failing alternator will ensure it can be replaced immediately. Do you need a new battery? Discover how long car batteries last with our helpful guide. Replace your old alternator and car battery with new ones by visiting your local Formula One Autocentres branch today. 

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