Abstract: A rear door assembly for a motor vehicle includes an outer door panel and an inner panel. The inner panel is fixedly secured to the inner surface of the outer door panel. The inner panel has a main frame having a generally transversely extending opening and a frame member fixedly secured to the main frame. The frame member extends between opposite sides of the opening in the main frame and extends along a bottom edge of the window opening. The frame member has a transversely extending upper flange and a lower flange spaced apart from the upper flange. The frame member has a main wall extending between the upper and lower flanges and forming a generally U-shaped cross section therewith. The flanges are directly fixedly secured to the inner surface of the outer panel and forming a transversely extending support beam therewith.