Removal of monowiper is pretty straightforward, remove rubberseals at the side, to get to two of the total of four screws for the plastic that covers the monowipermechanism.
Remove plastic cover, and the monowiper is fastened by a total of 3nuts and 2 screws
My problem was the different connections monowiper w201
Since the monowiper of my 1986 190d 2.5 died, (had no power/strenght in the motor, and wouldnt move unless in the air)
I tried swapping to a wiper from a 1992 2.5 turbo w201.
the contact did fit, but the wiring was different.
Old monowiper vs new monowiper, the left one has the contacts “stuck” in place, where the right one have a “cable”
Old one can be seen in the rear of left photo, the welded contacts of the new monowiper assembly on the right picture.
The contacts/wiring diagram did differ, and it didnt work, they also had a bit different layout, where the later one was a cable that you could detach from the wiper mechanism, while the stock w201 from 1986 was soldered in place on the gear-assembly
Since i had the possibility to swap places in the wired contact of the new wiper-mechanism that i put in i decideed to go there instead of swapping places on the contact on the car (as i would have had to do if it was a new car i put an old monowiper-mechanism on)
To the left is the wiring in the contact of the monowiper of a stock w201 from 1991, the right contact is how i switched places to get it to work properly on a 1986, it took some measuring and logic to get it right
this writeup isnt totaly clear, and i did it a long time after acctually doing the swap, i think this was how it was done, if you are doing it yourself, it ought to be self explanatory.