Symptoms of a Bad Alternator


When an alternator fails completely, you know it. In most cases, the charging light will light up on the dashboard and you may experience one or more of the following symptoms:

  • The engine crashes while driving due to power loss
  • Dimming the dashboard and headlights
  • Problems turning on the power vehicle
  • Repeated need to skip vehicle start-up due to discharged battery
  • Abnormal noise


There are a few different ways the alternator fails:

Under-load: When the alternator is discharging, the lights may dim or shake and the battery will be discharged. In this case, it is difficult to start the car. If you are driving the vehicle when the alternator goes out, the vehicle will eventually stop.

Overload: An overloaded alternator can result in short lamp life. In modern vehicles, an overload alternator can result in an illuminated engine light. It can also cause all kinds of problems with the electronic controls and the on-board computer.

Bearing noises: In some conditions, an alternator can still work properly, but it makes a lot of noise. Usually, the noise will be an acute buzzing that coincides with the engine rotations. This usually indicates that the bearings inside the alternator are failing.

In these conditions, take your car to Auto Repair workshop for maintenance.

How does an alternator work?

The alternator is the main part of the charging system. Not only does it charge the battery, but it also provides power to the entire vehicle when the engine is running. Without the alternator, your vehicle will die quickly.

To develop the current, the alternator depends on something called electromagnetic induction. This phenomenon occurs when a conductor is moved through a magnetic field, resulting in the production of electricity. Inside the alternator, there is a stationary set of windings, called a stator, and a rotating electromagnet, called a rotor.