Hi I had this problem with my '91 300SL. (This, I believe, is a warning chime to say the roof is not completely locked down, so not to drive). Inside the boot, at the top of the back wall both sides, there are the locking levers behind plastic covers. I had already locked the hard top down when the chime started when driving. I used the manual closing tool to lift the left lever one click, then clicking down again whilst leaning down on that corner of the roof at the base just above the boot. Get someone else to push down whilst you click down with the tool. I repeated this on the right side and it did the trick, no problems since, although I have not taken the hard top off since. Good luck, I hope this helps you-Matt