The electrical charging system is one of the most important systems on any vehicle. The charging system is made up of several components, including the alternator and battery, that work together to supply all of the vehicle’s electrical needs. The alternator is what specifically generates the amperage and electricity required to meet the vehicle’s electrical needs, including keeping the battery charged.

Because the alternator plays such a vital role in keeping all of the vehicle’s electrical components powered, any problems with the alternator can quickly develop into problems with another system or component on the vehicle. Usually, a defective or failing alternator will produce a few symptoms that can alert the driver of a potential issue, allowing time for the driver to service the vehicle before a bigger problem occurs.

1. Having to jump start the vehicle on a regular basis

One of the first symptoms of a bad or failing alternator is the need to jump start the vehicle on a regular basis. It is the job of the battery to provide the power to crank the engine and start the vehicle, however, it is the job of the alternator to make sure that the battery stays charged. If the alternator is beginning to have problems or has failed, it will not be able to meet the vehicle’s electrical needs, including keeping the battery fully charged. A low or uncharged battery will not be able to keep up with the load required to start an engine multiple times, and will result in a dead battery. Continuously having to jump start the vehicle may be a sign that the alternator may not be charging the battery and is therefore unable to successfully start a vehicle.

2. Dim lights

Another symptom of a potential problem with the alternator is dim or flickering lights. If you notice any sort of flickering or dimming of the lights when operating the vehicle, it may be a sign that the alternator is not generating enough power to keep up with the vehicle’s electrical needs. The dimming or flickering may coincide with certain actions when operating the vehicle, such as dimming when pressing on the gas pedal, turning up the volume on the stereo, or turning on another light. This symptom may be indicative of an alternator that is unable to keep up with the needs of the vehicle’s electrical system while it is running, and when additional loads are placed on it.

3. Battery Light comes on

One of the most common symptoms of a problem with the alternator is an illuminated Battery Light. The Battery Light will usually come on when the computer detects that the system voltage has fallen below a certain requirement. This usually means that the alternator, or perhaps one of its internal components, has failed and it is no longer able to keep up with the vehicle’s electrical requirements, and it has been detected by the computer. An illuminated Battery Light also indicates that the vehicle is now running on limited battery life. Depending on the condition of the battery, and how long the Battery Light has been on, the vehicle should be able to run for a short amount of time before the battery finally dies. At that point, the vehicle will shut off and service will be required.

The alternator is among a vehicle’s most important components, as it essentially serves to provide the electrical supply for the entire vehicle. Any problems with it can quickly translate to problems with starting and running the vehicle, which opens up the possibility of being stranded on the road. If you suspect that your vehicle may be having a problem with the alternator, or it is displaying any of the symptoms above, [have the battery and alternator carefully inspected] by a professional technician, such as one from YourMechanic. They will be able to determine if an alternator replacement is necessary, or if another issue needs to be addressed.

This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Alternator and was authored by Ed Ruelas.


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