Headlight main beam problem

[gpfalcon]

Hi Guys
Just took my car for a test (slk 320 r170) and the main beam is not working :failit is the only thing it failed on and I am hoping some can help. No problem with the fuses or the bulbs, I don't know where to begin to look for the relay, anyone got any ideas

 

[RichardF]

More likely the switch, start here. Does it work when you flash it?