Yes, you have to remove the instrument panel, but that is extremely easy. It just pops out as a unit.
I have a similar problem with the sunroof. Most likey it is probably needed cleaned and adjusted. You can DIY. Open it about half way and remove the headliner piece. You shoud see a cable. Remove the cable and try to manually move it back and forth. If it slides easily, it is your cable; if it does not, take the rails off and clean them.
1985 500SEL (260,000 miles) SOLD!
1974 280 SOLD!
1994 Volvo 850 Turbo Wagon (Yuppie Ice Sled)
"I know I have a Benz and they know it too." If you start bragging about it or shoving in people's face, you then become a Wally; especially to the girls.