Testing Your Alternator at AutoZone (2024)

Why Test Your Alternator At AutoZone?

If you suspect a bad alternator, there’s no better place to get it checked than AutoZone. If you bring it to your local mechanic or dealership, you’ll need to make an appointment, which could be days away. Then, you’ll need to drop it off or wait for hours without your vehicle until it’s been diagnosed. And once you get the results, there’s an invoice to pay for the alternator testing, regardless if it’s received a passing or failing grade.

An alternator test at AutoZone takes the stress out of it all. Whether you drive your car in for testing or have the alternator out of your car already, there’s no appointment required. It only takes a few minutes, and it’s completely free. Yes, you read that right. Free.

A failing alternator can manifest in different ways. Signs of a bad alternator can include:

• Flickering or dim lights
• Battery warning light illuminated
• Slow electrical operations like power windows
• Belt squeal or chirp
• Growling or droning under the hood, related to engine RPM
• Slow engine cranking
• And, of course, a dead battery

At the first sign of these symptoms, get to AutoZone. Our alternator test will help you determine what is causing your electrical issues. Our staff will help you find the right parts for your vehicle with brands you trust, like Duralast, and avoid unnecessary costs.

How to Test Your Alternator at AutoZone

If you aren’t sure whether it’s your alternator or battery failing, get a free, accurate alternator test at AutoZone.

Getting your alternator tested at AutoZone is simple and hassle-free. An AutoZoner can test your alternator while its still in your vehicle, saving you the hassle of removing it and re-installing it if it’s still good. Or, if you have the alternator out of your vehicle already, we can test it on the bench instead.

Not sure which location to choose? Luckily, all AutoZone stores can test it for you, and at no charge at all. Find an AutoZone location near you online – the easiest way to get directions, store hours, and see which services they offer.

AutoZone Alternator Testing Procedure

Alternator Test in Your Vehicle

The first – and easiest – testing procedure is to bring your vehicle to your local AutoZone for an in-vehicle test. One of the friendly staff will connect a portable tester to your vehicle’s battery before starting the engine. Once it’s running, the tester will determine if the alternator is producing sufficient voltage. They’ll also perform a visual inspection and listen for abnormal noises that could indicate the alternator is in poor condition.

In-Store Alternator Test

The second method is for alternators that have been removed from the vehicle. Using our Duralast DuraTest bench tester, the alternator is connected to a series of leads, and the assembly is spun. The computerized tester analyzes the results and indicates whether the alternator passes or fails, along with more detailed results on the screen.

It checks if the alternator produces between 14.0 and 15.0 volts. But the test isn’t complete there. Output is checked under load as well, mimicking your vehicle’s normal operation with various systems turning on and off, to determine if it keeps up with a load present. If it doesn’t pass either one of the tests, the test result is “FAIL”.

What to Know About Alternator Testing at AutoZone

From start to finish, your alternator test at AutoZone only takes a few minutes. After the quick and easy test, we’ll help you find the perfect replacement for a failed alternator from our vast selection in-store and online.

If the alternator passes, but you’re having trouble starting your car, it could be one of a few other issues. You might have a bad battery, a faulty starter, or even something as simple as a burnt fuse or fusible link that requires further diagnosis. Fortunately, we perform free battery and starter testing too!

What to Do If Your Alternator Fails the Test

Your alternator failed? AutoZone has a wide selection of new and remanufactured alternators to choose from. Regardless of what make or model you drive, we’re sure to have a solution for you. Install a new alternator yourself, or purchase an alternator from AutoZone and bring it to a mechanic of your choice.

For certain parts, like the alternator bearing, brushes, diode, or resistor, it may be possible to rebuild the alternator rather than replace it completely. This type of repair is for a more advanced DIYer, as it must be fully disassembled, the faulty parts replaced, and the alternator reassembled precisely.

Keep in mind that a replacement carries a warranty on the assembly – peace of mind above and beyond what you get with a repair. And for Duralast alternators, enjoy our Limited-Lifetime Warranty.

Maintenance Tips to Prevent Alternator Issues

Trying to prolong your alternator’s lifespan, or want to keep your new alternator in the best condition possible to avoid a premature replacement? Here are some tips:

• Check for loose connections regularly. They can cause high resistance and strain the system.
• Keep the battery terminals clean. Corrosion can interfere with charging and strain the alternator.
• Avoid adding accessories that draw large amounts of electricity to avoid overloading the system.
• Charge, don’t jumpstart. While jumpstarting can get you back on the road quickly, it stresses the alternator as it tries to replenish the battery. Slowly and steadily, charge the battery instead.
• Maintain a healthy battery. If the battery is failing, it can take out the alternator, too. Replace the battery to prevent the issue.
• Check belt tension and replace bad belts. A slipping belt can prevent the alternator from charging properly.

Visit any AutoZone location for a no-charge alternator test. We offer free parts testing for batteries, starters, and alternators. And when you need a new alternator, we have What It Takes To Do The Job Right.

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