mercedes benz c 350 class 2009?

[Mohammed]

I've mercedes benz c 350 class 2009 and the rotation function of the display screen controler doesn't work so i conn't select any thing from the desplay screen if i use this function. however, it was working previously in proper way

please advice

[KING]

Have you done any upgrades to it like a new sound system, etc. probably a blown fuse. I hope this info. is helpful.