The door for the vanity mirror (or the frame for the door) can break; due to a redesign, the mirror "cassette" will need replacement.
Car Problem Reports
Mercedes-Benz S600 Vanity Mirror Door May Break
Mercedes-Benz S600 Problem
Average Mileage: 75,000 mi (61,000 mi - 89,000 mi)
Visitor, 2004 Mercedes-Benz S600, 61,000 mi
Just purchased this vehicle from a dealership in Georgia so I'm not sure when the vanity door latch broke. When I swing the visor down the door of the mirror just swings freely.
Broken latch on vanity mirror. Will not stay closed.