I am just taking a guess here, but with my 190e, it looks like you can just take a screwdriver and pry up the panel to expose the switches....verify this before doing it!!! hehe
2000 C230 Kompressor
1988 190e 2.3 - 225K miles, owned for 7 years. I cannot say enough good things about this car. Very well built, even at 225 it ran like new.