My 1994 E320 Cabrio power top suddenly stopped working a few months ago. It was odd, one day it worked fine, the next day I just got a warning sound when the top was unlatched and the power button depressed.
Diagnostics by an independent mechanic and my local Mercedes dealer confirmed that the failure was in the power top control module (Part #124-820-45-26). Unfortunately, this part appears to be unavailable from any dealer or from the Classic Center.