I've got a 1999 e320 (W210). The sunroof has been acting up for a long time. Intermittently, when I would push the button to pop up the sunroof, it would open it. When I would slide the button back to open the sunroof, it would pop it up. Mind you this didn't happen every time.

Now it doesn't open all the way and makes the dreaded crunchy sound when trying to open. It sounds similar to the noise my rear window made when the regulator blew. Does anyone have any idea what the problem is or more importantly how to fix it? Or, does anyone have an idea of what it should cost to repair?

Thanks.