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Headlights And Dash Lights Flicker While Driving—What’s Wrong?

Your car's headlights and/or dash lights flickering can become hazardous events, particularly if these instances happen at night while driving. So what could be wrong if these lights are blinking? We researched some possible causes of these problems, and here's what we found.

Different underlying problems could cause the headlights and dash lights to flicker. Some of these possible issues are:

  • Defective alternator
  • Malfunctioning ignition switch
  • Damaged or loose battery connections

You should apply the correct solution based on the issue you found to restore proper function to your car's headlights and dash lights. Continue reading as we talk about these possible problems in greater detail. We'll also tackle different potential solutions to restore the condition of your vehicle’s headlights and dashboard lights.

Before you continue reading, let us say we hope you find the links here useful. If you purchase something through a link on this page, we may get a commission, so thank you!

A red car headlight photographed on detail, Headlights And Dash Lights Flicker While Driving—What's Wrong?

Why Are My Headlights And Dashboard Flickering?

A dying car battery is the usual culprit for the flickering headlights and dash lights. But if you recently had your vehicle’s battery recharged or replaced, then it might be defective or encountered malfunctions.

A detailed photo of a car headlight

But other underlying issues can also cause the headlights and/or dashboard lights to blink without human interference. Some of these possible origins might include (but aren’t limited to):

  • Faulty alternator
  • Broken ignition switch
  • Damaged or loose battery cables

Also, the headlight or dashboard wiring might be loose, stripped, or perhaps even cut. It’s best to avoid using your car, particularly at night, if you encounter these problems. If you’re driving at night and these issues appear, park the vehicle somewhere safe and contact a reliable towing service.

How To Fix An Alternator Without Replacing It?

Car headlight photographed up close

If you found out that your car’s alternator malfunctioning is the cause of your headlights and dash lights to flicker, remove it from the vehicle and place it on a flat and stable surface. Make sure that you place paper towels or pieces of cloth on the surface because the alternator can be quite dirty.

Also, different things can happen to the alternator that can cause it to break down or work inefficiently. Some of these potential problems are:

  • Low-quality spare parts
  • Crossing or mixing up the car battery’s connections
  • An unwanted power surge caused by using an incorrect jump-starting method
  • Corroded, filthy, or rusty fasteners or connectors

Keep in mind that the process of repairing the alternator often depends on the cause of its malfunction. So, troubleshoot the assembly first before attempting to do any repairs on it.

Moving forward, here’s a quick look at the process of fixing a car alternator if it has a broken diode plate:

What You’ll Need

  • Socket wrench
  • Flat-head screwdriver
  • Hammer
  • Pliers
  • Replacement diode plate

Step-by-Step Guide

  1. Start disassembling the alternator assembly by removing its nuts and bolts with the socket wrench.
  2. Remove more of the alternator by setting the flat-head screwdriver on some of the parts and whacking that tool with a hammer.
  3. Use the pliers to cut the regulator assembly from the rest of the assembly.
  4. Replace the diode plate on the regulator assembly.
  5. Return and secure the parts to reconstruct the alternator.

Check out this rotating rectifier diode kit on Amazon.

Keep in mind that disassembling and reconstructing the alternator often requires sufficient expertise in automotive repairs. If you feel that you don't have adequate knowledge on this subject matter, think about turning to automotive technicians for their professional vehicle repair services.

Also, watch the video below to take a look at how to troubleshoot an alternator to find the source of its problem:

Remember to park the car immediately if you also recently found out that your car has a bad alternator and you’re still on the road. Read our post on how long can you drive with a bad alternator to learn more about this subject matter.

How Do I Change My Car’s Alternator?

Car belt engine

You can skip the alternator repair process by replacing this assembly. Doing so should restore proper functionality to your vehicle’s different electronics, including its headlights and dash lights.

Also, replacing an alternator is often an easier job as compared to fixing the assembly. You may not also need any special tools for this task. But the replacement alternator needs to be compatible with your vehicle.

However, take note that you may still need to check your vehicle’s owner’s manual often. For instance, you need to find the location of the alternator in your car. Remember, different vehicles often have dissimilar frameworks, which also means different locations for their alternators.

Worker checking the alternator of the car

So the first step to this operation is to find the alternator in your car. Once found, continue this project by following these steps:

What You’ll Need

  • Ratchet extension set
  • Metal wire brush
  • Flat-head screwdriver
  • Torque wrench
  • Breaker bar
  • Serpentine belt tool

Step-by-Step Guide

  1. Take out the negative terminal connected to your car’s battery.
  2. Unscrew the intake hose and take it out from its fastener. Then, set it aside temporarily.
  3. Remove the filter and mass flow sensor, and temporarily set those aside as well.
  4. Use the serpentine belt tool to remove the engine belt through the tensioner/spring-loaded pulley.
  5. Use the socket wrench to remove the red terminal cable from the old alternator that would otherwise connect it to the battery.
  6. Remove the wiring harness on the old alternator with the flat-head screwdriver.
  7. Use the ratchet and the appropriate extensions to remove the bolts connected to the old alternator.
  8. Take out the old alternator from its bracket. Then, clean the alternator bracket with the metal wire brush.
  9. Install the new alternator while paying attention to its orientation.
  10. Secure the new alternator onto its bracket on the engine block.
  11. Return all the assemblies and components that you removed previously.
  12. Reconnect the negative terminal of your car’s battery.
  13. Ignite the vehicle’s engine to check if the alternator is functioning as intended.

Check out this replacement alternator for Ford E-Series vans on Amazon.

Our post on how much does a car alternator cost should help you estimate the amount of money you need to spend to buy a replacement for your vehicle.

How Do You Replace Car Battery Cables?

Take note that damaged car battery cables may make the vehicle's headlights and dashboard lights blink while driving. But these impairments might also make the automobile fail to start.

So the first step is to open the hood and check for any visible damage to the battery's cables. If you find some form of harm to these parts, you might need to replace them. If so, here’s a guide to help you in that regard:

What You’ll Need

  • Metal wire brush
  • Replacement battery cables
  • Wrench
  • Wire stripper

Step-by-Step Guide

1. Clean any corrosion on the battery’s terminal posts with a metal wire brush. But don’t use this tool on stamped metal cable terminal ends, for it may remove their protective coatings. 2. Disconnect the grounded battery cables from the battery. 3. Strip the new cable’s insulation to about 3/4-inch from its end. 4. Insert the bare ends of the cables to the correct terminals. Make sure that you’re attaching the correct cable to the right terminal. 5. Tighten the new cables and their terminals with a wrench.

Check out these replacement battery cables on Amazon.

The video below will show a visual representation of this process’ steps. It also shows how to replace the car battery’s terminals if needed.

How Much Does It Cost To Replace A Car’s Headlight Bulb?

Prepare to spend about $15 to buy a pair of replacement halogen headlight bulbs for your car. High-quality models exist, but the price to purchase these units may increase to about $50.

If the entire headlight assembly is malfunctioning, a reputable mechanic may charge you $50 for the inspection. This expense doesn’t include the replacement headlights you may need to purchase.

Also, the technician might need you to purchase a new headlight switch if it’s also faulty. If so, prepare to spend an extra $150 to $250 for this component.

How Much Does It Cost To Replace A Car’s Dashboard Lights?

Generally, automotive technicians will charge about $951 to replace the dashboard lights of vehicles. Although it usually doesn’t require special tools to replace these assemblies, you’ll most likely be paying the experts for their professional services.

Final Words

A red car headlight photographed on detail

Usually, it's the car's battery that's making the headlights and dash lights flicker while driving. Sometimes it can also be other underlying issues, such as a faulty alternator or a broken ignition switch. Make sure to troubleshoot the vehicle first before attempting repairs or replacements to avoid costly mistakes.