Central locking fuse keeps blowing

[RexHarrison]

Hi, I recently purchased a 2006 SL350 which has done 56k and is immaculate in my opinion. After owning the car for 2 months I discovered the red button (boot room assist) was not illuminated, I.e. not working. Looking on YouTube etc they said sometimes the cable becomes disconnected, so after removing the cover I found the cable had become disconnected, so I reconnected and the red light came on, this was when the roof was in the down position, I pressed the red button and there was a click but the boot assist would not operate. I put the roof back up and closed the boot, to find that the boot would not open again and the central locking would not operate. With the manual key I opened the boot, disconnected the boot assist button and located which I think is fuse No. 58 rear of driver’s seat and replaced this blown fuse with new. The new 25amp fuse blew. The central locking and boot opening had been working perfectly before I disconnected the cable. Does anyone know why the fuse is blowing now when everything is as it was? (PSE pump etc in boot is all dry with no rust or damp visible)