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Why Are My Headlights Flickering? 6 Possible Reasons

car headlight

Headlights are a critical part of any car, and when they fail, you’re literally left in the dark. While flickering headlights aren’t a severe problem, they can signal more serious issues. On the flip side, it might be something relatively innocuous. Let’s check out some of the possible reasons that cause car headlights to flicker, and how to fix it.

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Why Are My Headlights Flickering? (6 Possible Reasons)

1. Dead Battery

battery of a new car
Image Credit: BruceEmmerling, Pixabay
Severity Moderate

An old, faulty, or worn battery can cause some or all of your car’s electrical systems to fail. You can tell when a battery is going dead when your lights become dim and your radio shuts off. A typical car battery will last between 3 to 5 years depending on how much you drive as well as other factors.

If a dying or dead battery is the culprit of your headlight woes, you’ll first see flickering, and then the lights will go out altogether. The severity of your battery’s condition determines how fast that process progresses.

2. Excessive Auxiliary Power Drain

Custom car stereo
Image credit: Dave Reid, Pexels
Severity Low to severe, depending on system power requirements

High-powered surround sound stereo systems draw a lot of power, especially when the music has lots of bass. If you have a powerful car stereo, it can make your interior and exterior lights pulsate when the system draws power. The bigger the stereo, the more prominent the effect on your headlights will be.

Some other possible causes are faulty engine components, including a bad fuel pump, broken window motor, and malfunctioning air conditioning. When these parts break and stop working, they might still draw electricity, which builds up heat in the engine.

3. Dying Alternator

car alternator
Image Credit: Nordroden, Shutterstock
Severity Moderate

While the battery gets credit for starting a car, the alternator keeps the battery going. By converting chemical energy to electricity, an alternator charges your car’s battery as you drive. In ideal conditions, it takes about 30 minutes of continuous driving for the alternator to charge a near-dead battery.

So when an alternator goes bad, the battery doesn’t get enough electricity to start and run the car, which includes the lights. The voltage produced will spike and fall erratically until it fails completely, which makes headlights flicker and fade.

4. Faulty Wiring

a mechanic checking a worn out car
Image Credit: Qilin’s prance Filmmaker, Shutterstock
Severity Severe

This one is most prevalent in used cars where previous owners installed aftermarket systems and parts. Unfortunately, not all those owners are qualified to do the wiring. If wires get mixed up or damaged, it can cause the electrical systems to randomly go out. For headlights, this gives the appearance of flickering.

If you suspect faulty wiring is the cause of your flickering headlights, immediately take your car to a trusted professional. Bad wiring is no joke, and it could cause your car to catch fire and even explode if ignored. Seriously, don’t mess with electricity.

5. Loose Electrical Connection

car electrical repair
Image Credit: Joyseulay, Shutterstock
Severity Low

It comes as no surprise that your car’s electrical system has tons of wires, fuses, and assorted connections. When even a single one of these gets loose, you can notice flickering headlights. This is most noticeable on rough roads, where the bouncing rapidly connects and disconnects whatever part got loose.

It can be tricky to check the wiring harness yourself because when your car is still the loose connection might seem connected. We’d suggest asking a professional to diagnose more specific details.

6. The Bulbs/Lamps Are Worn Out

car headlight repair
Image Credit: DiPres, Shutterstock
Severity Low

Old bulbs and lamps in headlights will dim and fail over time, and flickering is one of the most common symptoms. While this is one of the most innocuous reasons for your lights to flicker, don’t assume there isn’t an electrical problem too!

To be safe, we’d suggest taking your car to have it checked by a mechanic. They’ll be able to confirm that the bulbs or lamps are the culprits of your flickering, and they’re trained to spot any other contributing irregularities too. Bad or loose fuses are especially common in older used cars.

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Final Thoughts

We’re sure you folks who thought your car was haunted are relieved to find out the real cause is far more mundane. Flickering headlights can indicate numerous problems, and some are more or less severe than others. To be certain, you should have your car checked by professionals.

Featured Image Credit: Piqsels

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