I have a 1999 slk 230. Recently the horizontal control for the mirror position will not function. I can hear the motor when I activate the switch. But the mirror will not move. The verticle control still works.
I appears something has come unhooked inside.

How do I get it apart to fix it? Is there some way to get it apart without breaking it?

 

I had the same problem not long ago, it was the motor behind the mirror that was bad & I replaced it with a new one.
Heres the how to http://www.buellwinkle.com/r170/exmirror.htm

 

Thank you!