W211 fuses

[e320dave]

Does anyone know whether the W211 estate has a fuse for the towbar electrics reverse pin as part of the standar fuse setup? The only reason I ask is that I do not get 12v on the reverse pin of my towing electrics any more (when in reverse and engine on) and I used to a few weeks ago.
Thanks

[e320dave]

Bit more googling shows that there were 2 candidates, both of which were empty. I'll contact the experts tomorrow to see if they can fix the right mess of wiring I found in the back there tonight.