Assuming you are referring to an issue with your car's Daytime Running Lights (DRLs), there are a few potential causes and solutions. One common issue is that the DRLs may be turned off accidentally when the headlight switch is moved to the OFF position. To fix this, simply turn on the headlights manually to re-activate the DRLs. If your DRL light is still not working after this, there may be a problem with the fuse or bulb. Check your car's owner's manual to locate the fuse box and look for a blown fuse. If you find one, replace it with a new fuse of the same amperage. You can also try replacing the bulbs if they seem burnt out or damaged in any way.