Well, no replacement yet, got fed up and pulled the original out, spent time disassembling it. Brushes look fine, comm was a bit cruddy. Polished it with #1500 wet-or-dry, reassembled with the case 180° from original. Works FINE now.
The main reason this was done is that this AM I went to meet with my Breakfast Club, pre-dawn, saw the rear window a bit fogged up and hit what I thought was the rear window defroster. Hit the sunroof by mistake. It worked just enough to open the seal and then wouldn't CLOSE the durn'd thing. On returning, decided Diesela and I needed to spend some 'quality time' together.
About a month ago the trunk lock decided to be in the permanently locked mode. Got that opened by going thru the rear shelf by removing the toolkit and not unlike those carnival game crane machines to pick up prizes, spent about half an hour with a piece of 1"x2" and a drywall screw in one end fiddling with pulling the mechanism to a point where I could depress the outside button and get access to the trunk. Disabled the auto-lock gizmoid and now just a matter of using the key. Encouraged, I progressed to the window motor, leaving the sunroof for the last conundrum. Went to some M-B forum answers, most were discouraging, "remove headliner..." etc. I know these mechanisms, most all German cars of the era all used the same one, including Porsce/Audi and I had been trained at Lanham, MD to fix 'em. A real PITA! Sat for a bit, mumblin' to meself, then decided it may be prudent to look in the fusebox first. Spun the designated ceramic fuse a couple times with CRC 2-26 on the fuse tips. YEP!! Sunroof closed!
All-in-all a productive day.