Due, in part, to the weight restrictions being placed on vehicles by local, state, and federal agencies, the need to equip vehicles engaged in transporting heavy loads with a means to measure and communicate the weight of the load being carried by the vehicle has increased. This has become especially important in situations where the vehicle is adapted for both highway and off-road travel, and the load to be transported is loaded at remote off road locations where conventional weight stations are nonexistent. In the past, an apparatus measuring and communicating the weight carried by a vehicle, such as a tractor-trailer type vehicle or the like used a conventional load cell to measure the load carried by the trailer portion of the vehicle. The output of the load call was thereafter transmitted to the operator of the vehicle along an expensive and custom made cable interconnecting the load cell with the tractor portion of the vehicle. This approach has several disadvantages in that uncoupling the tractor and trailer without disconnecting the cable between same broke the cable resulting in replacement of the expensive item. In addition, if the cable were disconnected, the environment in which the vehicle was operated frequently introduced mud or the like in the ends of the cable producing inaccuracies in the apparatus.
The present invention overcomes these problems of the prior art. By using data transmitter and receiver units disposed on the trailer and tractor portions of the vehicle, the present invention measures and communicates the weight of the load to the vehicle operator along a spare wire in the reach cable interconnecting the tractor and trailer and typically provided as standard equipment by the vehicle manufacturer. The present invention alternately can communicate the weight of the load to the vehicle operator along one of the trailer lighting circuit wires. In addition, the electronic circuitry within these units enables the present invention to operate with minimal susceptability to error introduced by the effects of the environment in which the vehicle is used.