A vehicle door assembly includes a door module and a door panel. The door module has a back plate with a periphery bearing attachment orifices defining a base plane. At least one guide rail extends in a rail direction in a rail plane offset from the base plane and has a connected edge and a free edge. The connected edge is attached to the back plate, and the free edge is shaped for slidably attaching a carrier plate for a window. The guide rail vertically protrudes beyond the periphery of the back platen. A void in the rail plane intersects a trajectory of the connected edge. The void provides access through the rail plane to the periphery of the back plate, wherein an attachment orifice is disposed in the void. The door panel has a central hole and attachment openings aligned with the attachment orifices of the door module.