What Causes an Alternator Not to Charge?

by Jen Davis
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Your vehicle may be experiencing alternator problems if the battery is constantly dying; but when you have the battery checked for problems, it maintains a consistent charge. The alternator is the part of your car responsible for maintaining the battery's charge. If your battery is not recharged by the alternator while the car is driving, the battery will eventually run out of power, and your car will stop working. There are several different problems that can cause your alternator to stop working.

Pulley and Belt

Your car's alternator charges the battery by generating power with a pulley and belt system. If the belt that controls that system snaps, stretches out or breaks, the alternator will stop working, and the battery will not charge. The same thing will happen if the pulley is somehow damaged, displaced or for whatever reason malfunctions and will no longer turn.


The alternator is powered by several different wiring mechanisms. If a wire is not attached properly, becomes detached or is inadvertently cut, the alternator will not have any power. If the alternator is not getting any power, it cannot turn the pulley and belt mechanism that charges the battery, and the battery will not charge.


According to EconoFix.com, some vehicles have a specific fuse for the alternator. If this fuse blows, either from age or a power surge in the vehicle, the alternator will not work until it is replaced. Check your vehicle's fuse box diagram to determine if your vehicle has a fuse for the alternator.

Computer Problems

In many newer model cars, specifically those manufactured since the year 2000, the alternator is controlled by the car's computer. If your car's computer is not functioning properly or has system problems, it may cause the alternator not to charge.

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