Horn u/s c220 2005

[big Al's C220]

Hi Everyone, my horn has stopped working, checked the basics, fuse traced to the fuse box in the engine bay. Not blown.
checked for voltage at the horn when steering wheel pressed. no voltage present.
Removed the Airbag assy from the Steering wheel, looks a bit complicated behind there! refitted it!
Anyone got any ideas?

Merry Christmas

 

[Dieselman]

Front SAM faulty.