This paper describes an economical rear obstacle detection system that eliminates the tractor to trailer cable connection using infrared (IR) wireless communication. The Trailer Subsystem operates whenever power is applied to the trailer from the J560 power connector. The subsystem transmits Obstacle Detection information to the tractor via an IR transmitter. The Tractor Subsystem is activated when the vehicle is put in reverse. Thus the entire system is active only when the vehicle is backing. During operation this subsystem receives and decodes the transmitted signal from the trailer and determines what, if any, warnings should be given the operator.