Mercedes-Benz 300SE Problem Report
Mercedes-Benz 300SE Closing Assist/Door Lock Issues Due to Pneumatic System Problems
Problems with the pneumatic system can cause closing assist and door lock issues.
the door closing assist only works 2-3 times after pulling fuse out in the trunk. Then it quits after an hour. - Visitor
Sounds like the motor is working and the roof is just off track & stuck closed.