Vent Control cog access / replacement R129

[Dougcsv]

I’m getting a rasping clicking noise on my 93 500sl which I’m sure I was told was a known problem with teeth getting stripped off the vent control ??
Does this sound about right and if so can anyone point me in the right direction for how to resolve it. I presume I need to remove the trim in the passenger footwell are to gain access ?
any help would be much appreciated...