It will be interesting to see what they say on Benzworld. My opinion based on alldata for a later 129 is that the problem is in your right soft top bow switch (A23s2). The control module wants to see 0 volts (switch open) when "up" and locked and is probably seeing battery voltage (switch closed).

The switch is in the right side of the trunk. A not very good picture is attached.

I'm not sure of this diagnosis, but it should be easy enough to check without disturbing anything.

Good luck.

Attached Thumbnails

 

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe