The top controller is located under a plastic cover inside the right rear storage compartment. It's just a black box and has no servicable components. I can't offer an explanation as to why the latches don't release properly except to suggest you check for binding and lubrication issues. You can try to re-sync the top controller by operating both windows totally up / down several times. The soft top controller seems to be one of the most often posted "issues" of the 129's. You can use the search function to find lots of information from other owners. Note that the control system evolved over the years and so information posted for at 1991 model may not be valid for your car, although the basic mechanism remained unchanged. Search soft top controller. BTW My own experince ( 1991 SL )has been that lubrication ( grease ) of various moving parts in the mechanism has hardened over time and required cleaning and a re-lube. My controller has gotten confused a few times too, but I can reset mine via the diagnostic connnector under the hood. I don't know if that's possible on a 1995 or later model.

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