One MMI Button Not Working
 

Hi Guys.
I have one MMI button (the car one) not working on my 2006 a8. The sunroof leaked onto the MMI while parked during a thunderstorm. It's acting like a fuse is blown. I checked the fuses in the trunk, they are all good. Does anyone know where this fuse might be located before I get any deeper into the problem?
Many Thanks,
Paul.