Your cable is probably stripped. Meaning the manual closing nut won't work. What you have to do is remove the headliner....undo the cable clip and open close the sunroof from inside the car.

This is a picture of a w115 but it's the same design.....the cable controls the black bar...this pops up and pops down the sunroof....once the cable is unhooked disconnected you can manually operate the sun roof with that bar.

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