Abstract: An on-board load weighing system for determining the magnitude of the load carried by a tractor trailer truck is provided. The weighing system includes one or more load sensors that are placed between the load platform on which the load is applied and the suspension system of the truck/trailer. The load sensors are connected to one or more transmitters. Each transmitter includes an on-board microprocessor that has its own memory. The microprocessors use calibration data stored within the memory combined with data provided by the load sensors to determine the magnitude of the load being applied to the load sensors. The transmitters then provide an indication of the load being applied to the load sensors to a master controller located in the cab of the truck. Each transmitter is connected to the master controller in a network. Upon power-up, the on-board controller interrogates each of the transmitters in the network in order to determine how many transmitters are present.