How Do Automatic Headlights Work? (Your Full Guide)

Automatic headlights promise to take the hassle of having to figure out which lights to use when driving, but you might be hesitant to make the switch.

Therefore, you may like to know more about automatic headlights before installing them. If so, keep reading to see what I learned about how automatic headlights work!

How Do Automatic Headlights Work?

Automatic headlights work by having sensors around the windshield and the instrument panel that read the amount of light in your surroundings. If the sensors determine that the light is low enough to affect visibility, they turn on the headlights. They also scan visibility to turn the lights on during weather events such as blizzards, heavy rain and fog.

Keep reading to learn everything you need to know about automatic headlights, including a closer look into how they work in different scenarios, how to control them and more!

How Do Automatic Dimming Headlights Work?

Cars with auto dimming headlights work by having sensors or cameras in strategic areas around the front that detect nearby vehicles so they can switch to low beams.

Sensors used in this way will have lasers that are fired ahead to map the road in front of you and, if they detect a car, they’ll dim your lights.

Manufacturers that use this technology will install several sensors in different areas to make it harder to create a false flag (e.g. when something is blocking light from reaching part of the vehicle).

They scan for both oncoming traffic and vehicles that you’re tailing because high beams affect any driver they’re aimed at, whether it’s directly or when it gets reflected through the rearview mirror.

How Do Automatic High Beam Headlights Work?

How Do Automatic High Beam Headlights Work?

Automatic high beams work by scanning your environment for other vehicles to determine whether the vehicle’s brights should be on or off.

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High beam headlights dazzle anyone they hit, whether that’s directly into oncoming traffic or when the beam gets reflected to the driver ahead of you from their rearview mirror, but they still serve an important purpose when you’re driving in poorly lit areas.

Automatic high beam headlights make it so you can have your high beams on in these environments, but they can switch to low beams by themselves when there’s someone else nearby.

How Do Toyota Automatic Headlights Work?

Toyota’s Safety Sense includes an automatic high beam headlight feature that works through the process described above; it uses an inbuilt camera to scan for the presence of other vehicles on the road and determine whether or not to turn the brights on.

This camera kicks in when you’re driving at over 50km/hr or about 31 mph at night to detect the presence of vehicles ahead of you. The camera searches for tail lights and headlights in oncoming traffic.

If the camera detects either light, it switches to low beams to avoid dazzling other drivers. It also scans your surroundings for environmental lighting from streetlights to determine whether your high beams are necessary.

Do Headlights Turn on Automatically?

Do Headlights Turn on Automatically?

Headlights turn on automatically only if your vehicle is equipped with automatic headlights and you’ve enabled them.

If your vehicle doesn’t have this system or you’ve set it to manual, then your headlights won’t turn on until you do it yourself.

Are Automatic Headlights Always on?

Automatic headlights are not always on, and only turn on when they detect that you’re in a dark environment such  as during the night or if you’re driving through a tunnel.

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Some are also set to turn on during weather conditions that limit your visibility, such as heavy rain, snowfall or fog.

How Do You Know If Your Car Lights are Automatic?

If you want to confirm whether your car lights are automatic, the easiest way to do so is by checking the switch to see if it has an AUTO setting.

You can also consult your owner’s manual. Automatic headlights are an advanced feature that manufacturers are always going to want to talk about, so if your car has them, it should be fairly easy to find in the manual without digging deep.

You can also check the manufacturer’s website, look for online videos about it or contact the dealership where you purchased the car to ask directly.

How Do I Turn on Automatic Headlights?

How Do I Turn on Automatic Headlights?

If your car is equipped with automatic headlights, you can activate the function by flipping the headlight switch to AUTO.

When the switch is in this position, the headlights will come on automatically depending on how dark it is where you are.

This means that if you turn the switch to auto during the day, the headlights will stay off until nighttime or if you drive into a tunnel.

In most vehicles, the headlight switch will be marked with icons representing different statuses, but the automatic headlight setting will almost always be clearly labeled with the word.

On the off chance that this isn’t the case in your vehicle, consult the owner’s manual, online resources or the dealership where you purchased the car to know where the setting is.

Turning off your automatic headlights also follows this same procedure; simply turn the switch from the auto position to either on or off depending on how you want them at the time.

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How Do I Turn off My Automatic Headlights While I am in Park?

Automatic headlights behave differently in different vehicles when parked, meaning that some will turn off when you stop the engine, but others may stay on until you take the key out of the ignition.

If you’re in park and the lights are still on, but you want them off without turning off the engine, the easiest way to do this is to turn the switch to the OFF position.

This will also disengage the auto headlight feature entirely, so if you want them to come back on, you’re either going to have to manually switch them on or re-enable the feature.

Do Automatic Headlights Turn on Tail Lights?

Automatic headlights turn on your headlights, as well as the tail lights, the same as it would be if you turned the headlights on manually.

If you’re referring to daytime running lights (DRLs), these don’t turn on the tail lights despite being automatic themselves.

If you want to learn more, you can also see our posts on why do headlights flicker, if headlights dim over time, and how long do LED headlights last.


Automatic headlights work by having sensors placed at different areas around the car to detect changes in light in the environment so they know when to turn on and off.

Automatic dimming or high beam headlights take this further by using sensors to detect traffic in the area so they can know whether to use brights or low beams. You can activate or deactivate this feature by flipping the headlight switch to auto.

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