Why Did My Alternator Fail?

There are a number of reasons why your vehicle’s alternator will fail and one of them is age. As with any machine part, the alternator wears down over time and must be replaced. There’s no way around it. Still, its failure could be caused by other problems around it, and Fairfax Auto Repair is happy to explain them below.


First, if you notice that your headlights are flickering or dimmer than they used to be, that’s a sign that you’re in for alternator trouble. If your headlights or other vehicle lights have something wrong with them electrically, they can also wear down the alternator prematurely. The more your vehicle’s electrical system is taxed the more trouble for your alternator.

Power Accessories

The same holds true for your power windows, power seats, computer system, entertainment system, etc. Anything that draws power from your battery uses your alternator. If any component is shorting or otherwise causing stress to your alternator, the result might be a dead alternator. This is why we offer electrical system diagnostic checks and services to our customers.


The alternator and battery work in tandem to keep your vehicle powered. As such, the two can stress each other. For example, since the alternator is what keeps your battery charged, a bad alternator can kill the battery. If your battery’s voltage is shorting out the alternator, this can damage the alternator. It’s important to install a battery with the right voltage for your vehicle.

Engine Stress

Anything that causes your engine stress or to overheat can also harm your alternator and cause it to fail. No machine part can withstand excessive heat; they all have thresholds. Your alternator is no exception, and if it’s surrounded by overheating parts, it will succumb to the high temperatures. Other stress such as worn down or seized bearings can harm the alternator.

Diode and Voltage Regulator

Finally, diodes handle your vehicle’s AC current and if your automobile’s diode fails, it might be leaking battery current through your alternator. This will wear down the part prematurely as will a bad voltage regulator. As its name suggests, the voltage regulator regulates the voltage between the battery and alternator. A bad one can damage both.

Fear not! Located in Fairfax, VA, Fairfax Auto Repair is a quick phone call away at 703-822-5911. We can run an electrical diagnostic on your vehicle to determine the health of your alternator.

Call Fairfax Auto Repair at 703-822-5911 for an appointment today!


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