Let me add my welcome from the "other side of the pond". Lots of good people here willing to help.
You can see all your wiring diagrams here:
http://www.autolib.diakom.ru:8001/CAR/Mercedes-Benz/1994/C280/SYSTEM%20WIRING%20DIAGRAMS/
Troubleshooting the window shouldn't be hard.
I bought my first Benz a little over a year ago and have found the on-line manual available at
www.alldata.com to be very helpful. It will only set you back about 25 dollars per year; many don't like the "useability", but there is a lot of information there. Now that I'm used to the way the info is organized, I can can find stuff pretty easy. The vacuum information provided on my S class is extensive.
Hope this helps.