PURPOSE: To put ON an another normal lamp in substitution when a wire breakage trouble occurs in a vehicle lamp, by utilizing the decoder means of a local area network device, in order to secure the operation of a load having the high importance degree related to the safe traveling and dispose of the trouble of the load itself, in particular to the wire breakage trouble of the vehicle lamp, even if the trouble occurs in the local area network device.

CONSTITUTION: A switching 6 connected with a prescribed local unit 3 is connected with the driving means 32 of other local unit 3. A load 4 is constituted of a plurality of vehicle lamps, and a detection sensor 5 for vehicle is connected with the vehicle lamp, and a wire breakage detection output supplied from the sensor 5 is connected with a decoder means 31.