A totally functional assembly includes on a base body (A) a lateral reinforcement, an internal opening control (2) and an external opening control (3) with antivibration sheet, an internal top reinforcement (5) of the base body, a lock assembly (6), a window-raiser (7), an antivibration bearing, a window and window-guides. This functional assembly can be mounted in the door after its appropriate operation has been verified. The window is introduced and placed on the rear guide of the door, bearing first on the locking area, and the fixing of the functional assembly is completed by using screws or the like in the zone of the hinges.