It does not open the door from within, only from outside.

Since you have disassembled the upholstery of the door moves the lever that accesses the opening from the inside, there are occasions that have a kind of regulator and others in which the rods are folded a little and the lever they exercise is not strong enough to open them, already disassembled it is just a thing to look and fix in the details, they are not a great complication but the causes must be observed and you can no longer do it, the rear, the rear Keychains that are those that make copies of keys can solve your problem, it is not complicated the problem is that you have to see it and be au to solve it