Daimler Trucks North America (DTNA) is recalling certain model year 2013-2015 Thomas Built Buses Saf-T-Liner C2, Saf-T-Liner HDX, and Minotour school buses manufactured August 5, 2013, through November 15, 2013 and equipped with IMMI-brand L9 seat belt buckles. When the button is pressed to release the seat belt, the latch plate can become partially engaged with the buckle, making the seat belt difficult to unlatch. Thus, these vehicles fail to conform to the requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 209, “Seat Belt Assemblies.”