fuse #1
 

I just noticed in my car's fusebox that the slot for the #1 fuse ("auxiliary fan") is empty. I assume there should be a fuse in there. What does the auxiliary fan do, and how come my car works (pretty much) fine without it?

I am not sure about Mercedes, but a lot of cars have "dummy", or empty fuse slots. Some cars of the same make/model are equipped with certain options/features, and rather than making seperate fuse boxes for them, they just put the same fuse box in all of them. I am not sure what the auxillary fan is though.