1. Control device for a luminaire of a vehicle, the control device comprising:an operating power input for receiving operating power;
an illumination output for directing illumination power to one or more light sources;
a power converter coupled between said operating power input and said illumination output for converting said received operating power into said illumination power, which illumination power is directed to said illumination output, the power converter comprising a control connection;
a control data connection for conveying control data;
a controller circuit coupled between said control data connection and the control connection;
a control power input coupled to said controller circuit, said control power input being separate from said operating power input, for receiving control power to said controller circuit independently of said operating power; and
a galvanic isolation between said controller circuit and said power converter, wherein the connection from the controller circuit to said control connection passes through said galvanic isolation.