Why Do Your Car Headlights Flicker : Causes & Fixes

Headlights Flickering

Many times, while driving on the road at night, the headlights of your car suddenly stop or the headlights start flickering. The flickering of headlights in vehicles is a serious problem. Because it can also become the reason for the accident in your vehicle. Headlights flickering can damage your vehicle’s wiring.

Through this article, we will learn in detail about the main causes of headlight flickering and how to fix it, so that you can fix the problem of headlight flickering in an emergency.

Why Do Your Car Headlights Flicker : Causes

Causes of headlights flickering include a dead battery, blown fuse, faulty electrical wiring, a faulty headlight bulb, a loose or corroded ground connection, or a faulty control module.

1. Loose Wiring Connections

car Loose Wiring ground Connections

To light the bulbs or tubes in the headlights of vehicles, a supply of DC current is given through wiring. But sometimes the wiring connections on the headlights become loose. Due to which the bulbs or lamps of headlights do not get sufficient supply of electricity, due to which the headlight starts dimming or flickering.

The reason for flickering headlights in vehicles can also be due to loose wiring connections and along with this problem, the negative ground connection of the headlights is loose, or corrosion accumulates in the battery ground joint.

2. Defective Headlight Bulbs or Lamps

Defective Headlight Bulbs or Lamps

Deterioration is a common process as the bulbs and lamps used in vehicle headlights age. The internal parts and components of old bulbs and lamps start getting damaged. Due to this, it has a direct effect on the light of the headlight.

And due to this problem, the headlight starts dimming or flickering. Bad bulbs and lamps can also cause dim or flickering headlights. So be sure to check the bulbs and lamps when the headlights are dim or flickering.

3. Bad Headlight Relay


Often, a power relay is installed in the headlights of vehicles to provide and control a sufficient amount of power so that the light from the headlight can be brighter. The power relay controls the power supply to the headlights. so that the flow of electricity going to the headlight runs parallel and the wiring can be saved from heating up.

But sometimes the headlight power relay gets damaged due to old age or water getting into the relay. Due to this, the headlight may be permanently off or extinguished. This again causes the headlights to dim or flicker due to a faulty power relay. So check the power relay if such a problem occurs.

4. Faulty Headlight Control Assembly

Headlight Control Switch Assembly

To control each function of the vehicle’s headlight, the control switch assembly is located near the steering wheel. by which the headlights are turned on or off and by this control switch, the high beam and low beam of the headlight are operated as per the requirement.

But the control switch assembly of the headlight wears out with age, due to which the electric power going to the headlight starts getting affected completely and sometimes the headlights may turn off permanently and sometimes the headlight starts dimming or flickering when this control switch assembly goes bad. So be sure to check the headlight control switch assembly when this problem occurs. If it is damaged, repair it or replace it with a new one.

5. Faulty Alternator

signs of a bad alternator2

In vehicles, the alternator is used to charge the battery. The alternator runs continuously as soon as the engine is started. The alternator turns out to be the output supply of DC current. through which the battery is charged and energy is supplied to other electric components of the vehicle.

The headlight and other components of the vehicle are operated by the alternator. But many times the alternator of the vehicle stops working due to an internal fault, which directly affects the charging of the battery and the light of the headlight.

A bad alternator can cause the headlights to dim or flicker and driving the vehicle with a bad alternator for a long time without charging can completely kill the battery and cause the headlights to turn off.

6. Dead Battery

Battery terminal corrosion

Generally, the life of batteries kept in vehicles is 3–5 years and after this time different types of problems start coming in the battery. such as a quick discharge of the battery, a completely dead battery, and no charging of the battery. The brightness of your vehicle’s headlights is directly dependent on battery power.

If your vehicle’s battery is dead or the battery is depleting its electrical energy too quickly, then the headlights of your vehicle become dim or the headlights start flickering. If the battery is completely dead, the headlights may turn off completely.

7. Heavy Music System

Heavy Music System in car

If you have a heavy music system in your vehicle and you play loud music, the amplifier in the music system is then powered directly from the high-current battery. If the engine of a closed vehicle is off, then listen to music in a loud voice. Then this heavy music system drains the battery power very fast.

And if you also kept the headlights on at that time, Then you can also see the headlights dim or twinkle as the music beats. At this time, the alternator is not getting charged due to the engine shutdown of your vehicle.

8. Brunt Headlight Bulbs Socket

burnt headlight bulb socket

Sometimes the sockets of the bulbs and lamps in the headlight get damaged due to old age or due to excessive heating. Due to which there is not enough flow of electricity in bad socket bulbs or lamps. Due to which the headlights become dim or the headlights start flickering and if the bulbs or lens sockets are badly damaged, the headlights may turn off completely.

How To Fix Headlights Flickering?

To fix headlight flickering, you must first investigate the reason behind it. After checking for these reasons, the problem of flickering headlights can be fixed.

  • First, check the battery. If the battery is in discharge condition. Then charge the battery. If the battery is dead, your only option is to replace the battery.
  • Check wiring harness and fuse. If you find any faults with these, then repair the wiring or replace the fuse with a new one.
  • Next, check the sockets of the headlight bulbs. If the socket is burned, replace it with a new one.
  • Check the headlight power relay; if the relay is bad, replace the power relay as well.
  • Replace the bulbs and lamps in the headlights if they are worn out.
  • Check the headlight control switch assembly. If there is any defect in this headlight switch, then you should get it repaired or replaced with a new one.
  • Check the charging of the alternator. because the headlights also start flickering due to a bad alternator.


Q. Why do my lights flicker while driving?

The main reasons why headlights may flicker while your vehicle is driving can be a bad alternator, loose wiring connections, and a faulty power relay.

Q. Can I drive with flickering headlights?

Driving with flickering headlights can also lead to a serious accident. Because of the flickering headlights, it is difficult to see the road properly at night and another vehicle coming from the front can also be confused by it. Because he has a wrong idea of the position and size of the vehicle.

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