Headlights and dash lights flicker when car is running (What to do?)

Flickering headlights and/or the flickering dashboard lights engine of your car can be a dangerous event, especially if it happens at night while driving. So, what could be wrong if these lights are flashing? We investigated some of the possible causes of these issues, and here’s what we found.

Various underlying problems can cause headlights and flickering dash lights. Some of these possible problems are:

  • Faulty generator
  • Faulty ignition switch
  • Damaged or bad battery connections

You must apply the correct solution based on the issue found in order to restore the correct operation of your car’s headlights and flickering dashboard lights. We will also look at various potential solutions for restoring the condition of your car’s headlights and flickering dash lights.

Why does the interior light go out?

Dim indoor lighting, like my dome light, often dims due to electrical issues with the bad battery, alternator, or voltage regulator.

To find out which one is causing trouble, check the bad battery voltage. A low value will tell you that the alternator is most likely to blame.

Be aware that a bad alternator can weaken the dying battery, so make sure the alternator issue is fixed right away.

If the technician determines that the alternator is working properly, the battery may be dead. A tech will have to check the dying battery by measuring the voltage to see if this is the cause.

Feel free to replace it if it starts to show signs of losing charge to avoid any inconvenient circumstances.

Not the alternator or battery? Check the ground wires. Loose ground wires can also dim the light.

Why is my turn signal blinking fast?

In most cases, a fast-blinking turn signal or turn signal indicates a burned-out light bulb.

You see, each turn signal has a flashing module that briefly stops the circuit that produces the flashing of the front and rear turn signal dashboard lights.

Turn signals work with a certain resistance, when the bulbs fail, the resistance changes its pace, flashing and clicking faster.

If my turn signal is flashing but the bulbs are fine, this could indicate a faulty turn signal relay, insufficient voltage, or a grounding problem.

Why are the dashboard lights flickering?

The alternator is an important device that provides power to electrical power components (such as electric locks, radios, etc.) and helps keep the battery charged while driving on the road. Although the alternator does not require special attention, it is important to notice when this component begins to wear out.

The alternator is not working well when you notice dashboard lights flickering or dimming headlights, the battery can’t hold a charge, unusual noises coming from the battery or belts, the battery light on the dash comes on or having trouble starting, or the engine keeps stalling.

A qualified technician can confirm if the alternator is causing the car’s headlights and to dashboard lights flicker when idling. While the alternator is likely the cause, a loose belt, bad wiring, a blown fuse, or a starter motor can also cause the car lights flicker.

The starter helps create the spark to start the engine. If the starter motor fails, this can result in a pulsing or flickering dash lights indicator on the instrument panel, as well as slow revs, no start, grinding, or free spinning.

Why are my headlights and dashboard lights flicker?

A common cause of flickering dash lights and dashboard lights flicker is a dying car battery. But if you have recently recharged or replaced your vehicle’s battery pack, it may be faulty or defective.

But other underlying issues can also cause headlights and/or indicators on the dash to flash without human intervention. Some of these possible sources may include:

  • Faulty generator.
  • Broken ignition switch.
  • Damaged or loose battery cables.

In addition, the headlight or dashboard lights’ wiring may be loose, broken, or even cut. If you encounter these issues, it is best not to use the car, especially at night.

How to fix a generator without replacement?

If you find that your vehicle’s alternator malfunction is causing your headlights and dashboard lights to flicker, remove it from your vehicle and place it on a level and stable surface.

In addition, various things can happen to the alternator that can cause it to break down or run inefficiently. Here are some of these potential problems:

  • Poor quality spare parts.
  • Swap or mix up car battery connections.
  • An unwanted power surge is caused by using the wrong jump-start method.
  • Corroded, dirty, or rusty fasteners or connectors.

Keep in mind that the generator repair process often depends on the cause of its malfunction. So, troubleshoot the build first before trying to fix anything.

Moving forward, here’s a brief overview of the repair process for a car alternator if it has a broken diode plate.

What will you need

  1. Socket wrench
  2. Flat screwdriver
  3. A hammer
  4. Pliers
  5. Replacing the diode plate


  • Start disassembling the generator assembly by removing its nuts and bolts with a socket wrench.
  • Remove most of the alternator by placing a flathead screwdriver on some parts and hitting this tool with a hammer.
  • Use pliers to cut off the regulator assembly from the rest of the assembly.
  • Replace the diode plate on the regulator assembly.
  • Return and secure parts to restore the generator.

Keep in mind that disassembling and rebuilding a generator often requires a fair amount of experience in car repair. If you feel that you do not have sufficient knowledge on this subject, consider contacting automotive technicians for their professional car repair services.

What happens when the headlights and dashboard lights flicker?

When you pair flickering headlights with flickering dash lights, the alternator is most likely worn out. A worn-out alternator usually needs to be replaced. A technician can inspect the generator and determine the best approach.

Other signs of a bad alternator are:

  • Glowing battery indicator.
  • Dim or too overly bright lights malfunctioning.
  • Faulty or slow-running accessories.
  • Car starting problems.
  • Frequent stops.
  • Growling or whining sounds.
  • The smell of burnt rubber if the generator is jammed.


Why do my lights flicker when my car is running?

If your car’s headlights flicker while driving, you most likely have a worn-out alternator. If you do not take action, this will lead to a serious failure of the electrical equipment of your car.

Would a bad alternator cause lights to flicker?

When the alternator is not working properly, it can cause the lights on the dashboard to flicker.

Why are all the lights on my dashboard blinking?

A possible cause is a defective alternator.

Can a bad battery cause lights to flicker car?

These flickering lights are a sure sign of a bad car battery.


It is usually the car battery that causes the headlights and car dashboard lights to flicker while driving. Sometimes it can be other underlying problems as well, such as a faulty alternator or a broken ignition switch. Before proceeding with repairs or replacements, be sure to troubleshoot your vehicle to avoid costly mistakes.

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