Sunroof won't work, but I hear motor running
 

As the title says my 1985 300D has a sunroof issue. I pushed the button to open it and it opened right up. Went to close it and nothing but the whirring sound of the motor running. I did a search here and read about the nylon nut in the trunk that permitted manual operation. I used it to close the sunroof. Now when I push the button I get nothing but motor sounds, it won't open or close. Just the "whirrrrrr" sound of a motor turning. Anyone have any ideas?

Time for a new cable.

b4 you start replacing parts, check that the adjusting nut in the trunk is tight. It may just be loose and the rod is slipping.