5 Symptoms of a Bad Car Alternator 

Last Updated on June 24, 2019 by themechanic

If you don’t know anything about cars, then you might assume the car battery supplies all the electricity to the vehicle. The truth is the battery only assists in creating the electrical spark needed to help start the vehicle. Once the engine is running, the alternator supplies electricity to all the electrical components of the vehicle, including the stereo, headlights, radio, and air conditioner. The battery alone wouldn’t be powerful enough to energize all these components.

An alternator generates power by turning mechanical energy into electrical energy. This is what happens after you turn over the engine and get it running. There are all sorts of internal parts in an alternator, including a rotor and brushes. It normally takes about 3 to 5 years for these parts to wear out. Once they do, you’ll experience symptoms right away because the electricity of your vehicle will be affected.

5 Bad Symptoms

Anytime your vehicle has electrical problems, it can likely be attributed to either the car battery or the alternator. A lot of people have trouble distinguishing the symptoms of a bad battery versus a bad alternator. To help you recognize the difference, below are the top 5 symptoms of a bad car alternator for you to look for.

1) Warning Light

A warning light should illuminate on your dashboard when your car alternator starts going bad. This warning light may be a Check Engine warning, or it may be a Bad Battery warning. Since a bad alternator can affect the engine and battery, the car normally responds by indicating one of these areas are affected.

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2) Flickering Lights

The first big symptom that you’ll notice is your car’s dashboard lights and headlights starting to flicker and dim. You’ll notice this even more at nighttime when it is dark outside. The lights may stay dim for a few seconds and then go back to being bright again. This usually means it is a bad alternator rather than a bad battery. Hopefully, you’ll have enough light to safely get your car home or to an auto shop if there are any open.

3) Strange Noises

A sure way to know that your alternator is bad is when you hear strange noises coming from it. There is a serpentine belt which normally spins the pulley of the alternator. If the belt is too stretched out, there won’t be an electrical charge produced. This causes a squealing sound to occur. Alternatively, if the alternator has worn out bearings, then a grinding noise may happen.

4) Slow Electrical Devices

The electrical devices of your vehicle won’t operate to their fullest potential if the alternator is bad. For instance, if you have power windows or power seats, they will be much slower when you attempt to operate them. This slowness is the result of not enough power to move them faster. Also, you may try to use the radio and notice it shutting off by itself too. Take these as signs that you need to replace your alternator immediately.

5) Engine Stalling

The fuel injectors are powered by electricity from the alternator. As you may know, fuel injectors supply the engine with the fuel it needs for combustion. But if you have a bad alternator, then it cannot properly charge the fuel injectors. This means the engine won’t receive enough fuel. As a result, your engine will stall as you’re driving. You may also notice your engine stalling within a minute after starting your vehicle too. If your Check Engine warning light comes on while this happens, you will know for sure that your alternator is bad.

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