A friend of mine has a 1997 C280. I just changed the low beam bulb on it for her and in the process, broke off a clear plastic rod about 2 inches long that sits in a socket next to the high beam bulb.

What is that for? I looked at the other one (on the other side of the car) and have no idea what it is supposed to do. It has some black lines marked on it and seems like it the base of it is in an electrical socket, but I couldn't tell for sure.

Thanks.