as i see u can speak frensh soo vous pouvez me fournir plus d'explications en français :D je suis interesser par une e36 cab mais apres ça je doute

Check the wiring on the drivers side of the top where the top folds in the center the wires break and short with age where they flex. Every time you disengage the motors the top must be initialized. Also the top tension straps are not tight and it appears that the rods on the drivers side under the top cover are not adjusted properly. You're best bet is to convert it to a manual top. Too expensive to get it working correctly car isn't worth what it would cost to fix it.

BMW is known for its electrical problems. Whats new??