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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 left in the dark. Driving without functioning headlights is dangerous and illegal. While flickering headlights aren’t a severe problem, they can signal more serious issues. On the flip side, it might be something relatively innocuous and inexpensive to repair. Let’s check out some of the possible reasons that cause car headlights to flicker and how to fix them.

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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-out 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 dim and your radio shuts off. A typical car battery will last 3 to 5 years, depending on how much you drive and 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. 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.

Some other possible causes are faulty engine components, including a bad fuel pump, a broken window motor, and a malfunctioning air conditioner. When these parts break and stop working, they can 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. An alternator charges your car’s battery as you drive by converting chemical energy to electricity. In ideal conditions, the alternator takes about 30 minutes of continuous driving 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, 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 is more prevalent in used cars where previous owners installed aftermarket systems and parts. Unfortunately, some owners aren’t qualified to do the wiring. If wires get mixed up or damaged, it can cause the electrical systems to go out randomly. For headlights, this gives the appearance of flickering.

If you think faulty wiring is the cause of your flickering headlights, immediately take your car to a trusted professional. Bad wiring is dangerous and could cause your car to catch fire and explode if ignored.

5. Loose Electrical Connection

car electrical repair
Image Credit: Joyseulay, Shutterstock
Severity Low

Unsurprisingly, your car’s electrical system has several wires, fuses, and assorted connections. When even one wire becomes loose, you’ll 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 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 dim and fail over time, and flickering is one of the most common symptoms. While it 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

Car repairs are more expensive than ever, but depending on why they failed, headlights are more affordable to fix than other parts requiring higher labor costs. Repairing or replacing your lights promptly will get you on the road faster and prevent expensive tickets from law enforcement officers. Flickering headlights can indicate numerous problems, and some are more severe than others. To be certain, you should have your car checked by professionals.

Featured Image Credit: Piqsels


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