Headlights are among the most crucial safety components for night driving. If these lights stop functioning properly, driving becomes impossible. The situation gets worse when they start to act by themselves.
But why are the headlights turning on and off by themselves? The primary reasons include a faulty wire connection, a damaged fuse, a bad switch, a faulty relay, etc. Sometimes, if the bulb is passing its last phase of life, it starts to act by itself.
Here, I detail all these reasons along with the solutions to the issue. So, without any further ado, let’s get into it!

Table of Contents
Quick Table: Causes & Solutions of Headlights Turning On and Off by Themselves
The table below is designated to provide a brief overview regarding the causes and solutions of the automatic headlight turning on and off issue.
Causes | Solutions |
---|---|
Faulty wire connection | Replace the faulty wire |
Faulty headlight fuses | Replace the bad fuse(s) |
Faulty headlight switch | Fix the looseness and use dielectric grease on the connector pins |
Bad Relay | Replace the bad relay |
Ending of the bulb lifespan | Replace the bulb(s) |
Causes & Solutions of Headlights Turning On and Off by Themselves
In this section, I added a detail discussion on the causes of a faulty wire connection and also provided the solution in a detailed manner.
Faulty Wire Connection
The headlights on and off are controlled by the headlight switch on the dashboard. This switch and the bulb holders are connected with complex electrical wiring. There is also another set of connections: a light socket to the battery.
If there is any unshielded or bad wire due to the movement and vibration of the car, the positive and negative are contacted. The result is the headlights become activated and deactivated even though you do not touch the headlight on/off button.
How to Solve?
Below is the step wise guideline to solve the faulty wire connection issue.
Step 1
Park the car on the flat space and switch off the engine. Now, open the hood.
Step 2
Remove the front bumper and the central support by using a torque wrench as per the associated screw threading. In general, there are three screws at the top part and two screws at the bottom part holding the central support unit to the main body.
Step 3
Now, remove the sidewalls by unscrewing the fixation or attachment. You will see rubber dampers on both sides; remove those as well. There is a bolt holding the final protection plate. Remove the bolt and the protective cover.
Step 4
Detach the headlight wire connection from both side’s headlights. Also, detach the connection from the battery end.
Step 5
Take a picture of the wire housing. It will help you when you do the re-connection work. As the whole wire is now visible, do a primary visual inspection. But it is better to take out the whole wire and check properly.
Step 6
If you find any unshielded portion, cracks on the wire, etc., repair that portion. If there are multiple issues, I suggest you replace the respective wire.
Step 7
Now, without laying the wire properly, provide a temporary connection with the battery and headlight.
Step 8
Go to the driving seat, switch on the engine, and turn on/off the headlights several times. If those are working accurately, disconnect the wires and lay them properly using the picture after switching off the engine.
Step 9
Give connections to the headlight and battery. But don’t fix the central support. Start the vehicle and try to create vibration by pressing the accelerator. You will see the issue is fixed; the headlights are not working by themselves.
Step 10
Fix the central support, rubber dampers, etc.; all the parts reverse way.
Check out this YouTube video to learn the fixing process of the wiring issue of headlight assembly:
Faulty Headlight Fuse
The headlight fuses are designated to protect the whole light setup from excessive current flow. If the fuses are faulty, it can cause unnatural current flow through the circuit.
By the way, even your car’s key fob may not work due to a blown-out fuse. The result is headlights get on and off by themselves when they receive power.
How to Solve?
Below is the step-wise process to check and replace the faulty fuse(s).
Step 1
Open the fuse box. It is usually located on the driver’s side under the dashboard. On the cover, check the diagram to identify the fuses for the headlight.
Depending on the car’s brand and model, there can be a single or multiple fuses. If your car has a 55 watts headlight bulb, you will see a 15-amp to 20-amp fuse.
Step 2
Use a test light to check the status of the fuse(s). Touch the tester’s lid to the positive side first and then touch it to the negative side. The fuse is gone if the tester’s light is not lit for any one side.
Step 3
Replace the faulty fuse(s). The headlights will now work properly.
Faulty Headlight Switch
If the headlight switch is faulty, you can experience that your car’s headlights are working themselves. In this case, the switch becomes sensitive due to looseness or damaged connector pins.
When the car starts moving, the switch sends activation and deactivation signals to the headlights due to the respective vibration in the car. Finally, the headlights start to work by themselves.
How to Solve?
Here, I provide detailed guidelines to solve the headlight switch issue.
Step 1
First, you have to remove the steering wheel’s column cover. It is locked using clipping technology. Press the upper part and insert a flat to release the clip holdings. Remove the upper and lower part of the column setting.
Step 2
Check if it is loosely connected to the base. Tightening can solve the issue. But I suggest you check the inlet of the electric connector as well.
Step 3
Take out the electric connector. Check all the pins’ conditions on the connector.
Step 4
Put some dielectric grease on the pin if you see any rust or decolorization.
Step 5
Reconnect the electric connector and set the cover. The issue of headlights working automatically is gone.
Faulty Headlight Relay
The headlight relay ensures smooth and functional connectivity between the battery and the headlight bulb. If it becomes faulty, the power distribution goes out of control.
When you start the engine, you see the headlights are automatically turning on and off. Here, you need to replace the faulty relay.
How to Solve?
The following is the step-wise guideline to replace the faulty headlight relay.
Step 1
Locate the headlight relay at first. Depending on the brand and model, it can be located in the fuse or power distribution box.
Step 2
Wear the dielectric gloves and take out the relay. It is a rectangular box with three connector pins.
Step 3
Examine the relay; you will see burn signs on the connector pin or the relay body.
Step 4
Install a new relay. I suggest you be careful when purchasing the new relay switch. Ensure the old one’s part number to all the ratings match properly.
Step 5
After installing the new relay switch, close the box. And start the engine. You will see the headlights have stopped working automatically.
Ending of Headlight Bulb Lifespan
If the headlight(s) bulb passes its last life span phase, it can lit automatically. Here, the reason is that the brittle filaments retain some power in it. So, while the vehicle is on the go, due to vibration, the filament allows the power to pass through, illuminating the bulb. Here, the symptoms are dimmed light, light color is yellow, etc.
How to Solve
The following is the process of changing a headlight’s bulb.
Step 1
Open the hood and reach the headlight assembly’s backside. You will find a socket holding the bulb with the headlight assembly.
Step 2
Take out the socket and be careful about the respective wirings.
Step 3
Rotate the bulb’s end portion clockwise to lose it. Then, take out the old bulb.
Step 4
Install the new bulb and fix the socket again.
Final Words
I hope that now you have a clear understanding of why headlights are turning on and off by themselves. By replacing the faulty wire, fuse, etc., your issue will be solved. However, I suggest you prioritize the fuse and relay issue on top of all.
Finally, I highly recommend you consider some crucial concerns while purchasing the new items. Ensure the new wire, fuse, relay switch, etc., matches the manufacturer’s manual book requirements.
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