The alternator is a generator that produces electricity to power the car’s ignition system, lights and accessories. The engine drives the alternator by means of a belt, either with a dedicated belt or a belt shared with other pulley-driven components. An alternator will stop immediately if its drive belt breaks, but alternators can also fail over time and with use, requiring replacement. Failing alternators can result in repeatedly drained batteries, dimming headlights and localized noise.
