I've been reading lots of threads about our beloved sunroof, and couldn't find anyone with this exact problem.
I have a 2002 c230 coupe with the sunroof/moonroof, and a couple weeks ago this started happening:
-The shades seem to open and close, but you have to try hard with the button to open the roof (without forcing anything, it eventually opens up and back).
-When NOT pressing the switch, the motor does a "clack" "clack" repeating noise (as if the motor is trying to move something but it can't). Every time it does the noise (happens as much as once per second), the lights on the top will blink.
-I've tried all the reset procedures, and the problem persists. Sometimes, the clack clack stops, but after turning off the car for some time, the noise comes back.
Since the noise is very annoying, I tried disconnecting the plug on the top console, which doesn't solve the issue. Instead I removed fuse 9 which "works", but in-utilizes the whole top panel (i.e. no interior lights).