If your car or truck has headlights flickering or other electrical problems like dim dashboard lights, find out what parts could be the cause and the symptoms you’ll find when they start to wear with tips from our expert mechanic Andy.
Parts That Can Cause Flickering Headlights, Taillights, and Interior Lights
Usually the battery is at the center of any electrical problems your car or truck might experience, like headlights or interior lights flickering or the vehicle not starting. Sometimes related parts like the alternator, serpentine belt, and belt tensioners can cause problems with electrical components in your car.
Steps to take for electrical problems with your car or truck, like headlights flickering
- Check the Battery
The battery is the first part to you’ll want to check when you have an electrical issue. Make sure its charged properly and test it with a tester. Check the battery terminals and make sure they’re clean and tight.
More on how to inspect battery terminals
More on how to test a battery - Check the Starter
The starter is usually placed close to the engine and transmission bell housing on most vehicles. Symptoms for a faulty starter include a clicking sound or no noise when starting the car. The click won’t chatter like you would hear with a bad battery, but a single click.
In an emergency, you can have an assistant tap the starter with a hammer while starting the car, but this also means the internals are failing and the starter will need to be replaced.
More on starters - Check the Alternator
A serpentine belt drives the alternator, which sends charge to the battery. Symptoms for a bad alternator include a battery light on the dashboard turning on, and flickering lights like headlights or dashboard lights not working properly. There will more likely be a problem with exterior lights than interior lights. You may also find the car doesn’t start and the battery is dead, which can mean the alternator is not charging the battery enough.
More on how to tell if the problem is with the alternator or the battery - Check the Serpentine Belt
You’ll need a serpentine belt and tensioner in good condition for the alternator to work properly. If the belt is not spinning, it could cause the alternator to not charge properly. If a pulley like an idler pulley or the alternator pulley has seized, that can cause will cause belt to fall off. You may think a new belt will fix this problem when it’s a pulley.
More on how to inspect a serpentine belt
More on how to inspect idler pulleys
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Hello,
Thank you for your help but my symptom is not covered.
I have a 2003 Ford Explorer XLT. My headlight flickering only occurs when the headlights are in the off position never when on. One headlight flickers more than the other. The flickering continues after the vehicle is turned off then dissipates quickly. I have ruled out my battery, alternator, belt, starter, and light switch. There is no other dimming of any other lights and vehicle runs great. Also, do not have DRL on this vehicle.
I have no other problems other than having a hard time getting the vehicle “readiness” set for inspection. I’m thinking it’s a wiring or ground problem but would sure appreciate any suggestions. I am desperate at this point as my inspection is 2 months past due. Thanks.