What is a light sensor? Does my vehicle have a light sensor?

There are a few ways that you can tell if you have a light sensor. The easiest is if your lights turn on or off automatically depending on how light it is outside. If they do have that functionality, you probably have a light sensor installed on your vehicle. The light sensor itself is usually mounted on your windshield next to the rain sensor, behind the rearview mirror or on the dash near the windshield edge.

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How does a light sensor help my driving?

It is there to support the field of vision of the driver, making the usage of the headlights more efficient. Using sensors that detect the ambient light, or illuminance, around the vehicle, this system will automatically turn on your lights if it is getting too dark. If you are driving for an extended period of time into the night, you may not notice how dark it is, which could be dangerous for other drivers who rely on your headlights to note your position on the road. To save your vehicle’s battery life, these sensors will also turn off your headlights, too.

If my windshield is cracked or chipped, do I need to replace my light sensor?

Windshields with small cracks or chips can usually be repaired if they are small enough, helping you avoid replacing the light sensor. If your windshield has a crack that is larger than a dollar bill, then it really should be replaced, along with any technology systems attached to the windshield. Light sensor systems are available for purchase on the market, but OEM re-installation is the best way to ensure that it will function properly. If installed poorly, the illumination detection may turn the lights on when not needed, thereby draining the battery, or not turning on when it is needed. 

Light Sensors and Replacement

Should you need to replace your windshield or auto glass window, inspect the light sensor to see if the wiring is intact, as you may need to purchase a new sensor if the wiring is damaged. Acquiring as much information about your vehicle prior to the auto glass service will better inform Safelite technicians in how they can help you replace your auto glass and get you back on the road quickly.


To learn more about glass technologies 
that can affect getting the right windshield, please select from below. Visit glass parts to discover more the different types of glass in your vehicle.

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