Heavy duty semi tractors like the International Prostar don't typically use standard OBDII ports. Therefore, in order to use the Tuson DirecLink Base Model Trailer Brake Controller part # 335DL-100 you'll need an adapter like the Tuson Heavy Duty Truck Module Kit for DirecLink Brake Controller; part # 335HDCON-6PIN for 6-pin or part # 335HDCON-9PIN for 9-pin. view full answer...