Signs of an Alternator Problem in a Car

Updated February 21, 2017

The alternator is the heart of the car's electrical system. It is the point where the car's electrical connections originate and supply power to all the parts that require it. The main parts of the electrical system in the car include the fans that cool the engine, the headlights, ignition coils, the air conditioner and the music system. Although the battery is the main source of power to these parts, the alternator ultimately drives these systems. In other words, it is the link between the fuel tank and the battery, and is the source of power for the battery. The alternator does not produce energy but converts mechanical power from the engine to electrical power.

Engine Losing Power

If the engine begins to lose power, this can be one major sign of an alternator problem. Alternator problems show up in stages, mainly because even when it is not supplying power to the battery, the battery continues to run for a while because it has some reserve power. However, the voltage drops if the alternator isn't supplying energy. The bearings on the rotator of the alternator may produce a creaky noise as the alternator loses power as well. This combination of loss in power and increased noise is one way of determining that the alternator is malfunctioning.

Catalytic Converter Burning

In some cases, the catalytic converter can catch fire as a result of a problem with the alternator. When the battery is not fully charged, and the alternator is not functioning properly, unused fuel can get into the catalytic converter, where it can ignite.

Low Headlight Illumination

Decreased output from the headlights is another sign of an alternator problem. If the headlights are dim, even after switching off all other accessories that use the battery's power, such as the air conditioner and stereo, the alternator is most likely to blame. Using a voltmeter is a simple method of determining if the loss of power is due to problems with the alternator. If the AC scale shows voltage of less than 14, then it is a sure sign of a problem with the alternator.

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About the Author

Alexis Writing has many years of freelance writing experience. She has written for a variety of online destinations, including She holds a Bachelor of Arts in communication from the University of Rochester.