How Long Does an Alternator Last?

Your car battery and alternator work together to provide electrical energy throughout your vehicle. You can't have one working without the other (or at least not for long). Specifically, the alternator charges your battery and powers your electrical accessories. Once your car battery uses up the energy to start the car, it needs to be replenished. And the alternator does so whenever your engine is running.


While vehicle batteries can last most drivers between 3-5 years, how long does the alternator last? An alternator can last longer, up to 100,000 miles in fair conditions. Whenever the alternator grows weak, you may notice your electrical accessories malfunctioning (ex., flickering headlights, dim lighting, and problems starting the car).

Below are some tell-tale symptoms that you should have your electrical components tested:

  • Bad Odor – A burning scent coming from under the hood could mean many things, including an overworked electrical system.
  • Weakened or Drained Battery – Since the alternator is responsible for replenishing the battery juice, your battery will eventually run out of power. Therefore, a dead battery necessitates an alternator check too.
  • Malfunctioning Electrical Components – As mentioned before, dim or blinking lights are popular symptoms of a bad alternator. Additionally, your power windows, power seats, radio, windshield wipers, and even steering wheel heating can stop working.
  • Odd Noises – There are a lot of things spinning when the alternator is working. If there is a mechanical problem within the alternator, you may hear a whining or grinding sound. 
  • Dashboard Warning Lights – Last but not least, your car may alert you through a symbol or message, indicating that one or more of your electrical components is malfunctioning.

If you suspect you need alternator repairs, we invite you to bring your vehicle to our Houston auto repair shop. Please give The Auto Doc a call or schedule an appointment online with us today.