Remove rear seat base (allen key under seat front) and unclip rear side panels - tricky bit is unscrewing where panel meets rear seat yoke, all others are plastic clips. Sensors there tell if cover is on, so be careful. You may have to have the roof almost retracted to reach the screw. behind the panels are the lifts. There are 2 hydraulic lifts, one on either side. Check for fluid leaks... seals are old. Accumulator & fluid fill point is behind LHS rear light (RHS is central locking air motor). Controller checks sensors, only activates hydraulics when cover is off, car is stopped, gear neutral and brake applied... uses some of the central locking sensors.
I also have 96 Cabrio, my roof never worked... I stripped her down to chassis and rebuilt her, thats how i figured it all out. Frankly i'm happy working the roof manually, its quicker. plus, you can drop the top at speed. Not recommended but it is fun. Just love that car.
