Headlights

If you have them locked open it is probably the headlamp door motor chattering trying to close them. If you want them open all the time you can just remove the trim panel and unplug the headlamp door motor power connectors. They are located on each motor on each side. dip the ends in some grease and wrap them in a small baggie in case you decide to repair the drive units at a later date.

If you want to repair the units there are places online where you can get kits that replace the gears. You can get plastic or metal.
This is a pretty good video showing how they come apart and how to flip or replace them.
https://www.youtube.com/watch?v=0m0n5xewcn8