The wiring needed to control all the functions in a vehicle is reduced, especially where the input source for operating a given function is remote from the function. A control member is provided that receives the input signal and converts it to a coded message that is applied to the power line. A function controller includes a coded reader and a control circuit for reading the code applicable to its associated function and controlling the function as instructed from the input signal. The control member also monitors the power line to insure that the message has been properly sent, and the message is repeated until proper transmission is confirmed.