Modular power running board

A motorized retractable running board assembly (10) for a motor vehicle comprising: a housing assembly substantially hermetically sealed (12); a stirrup (17) having a linkage system parallel (14 15) pivotally mounting the stirrup (17) on a vehicle for pivotal movement about generally vertical axes between a position retracted or storage under the vehicle and a position Unfold extending out of the vehicle, said running board presenting (17) an upper bearing surface; a gear assembly (20) disposed in said sealed housing assembly (12) and coupled to an arm (14) of said parallel linkage; a motor (18) assembly coupled drivingly with said gear assembly (20), wherein said motor (18) assembly operable to pivot said running board (17) between said positions deployed and retracted; one stop structure (300) positioned to engage said arm (14) of said parallel linkage when said running board (17) is in said deployed position, and characterized in that said stop structure (300) includes a movable structure (306) disposed at an interface between said stop structure (300) and said arm (14), and a spring member (308) biasing said movable structure (306) towards a first position, wherein said movable structure (306) prevents movement of said arm (14) beyond said deployed position, wherein said movable structure (308) is movable against the pressure member mentioned spring (308 ) to a second position allowing movement of the arm (14) beyond said deployed position when an external force to said bracket (17) exceeding a threshold value is applied.