The control device for the luminaire of a vehicle has an operating power input (401) for receiving operating power, an illumination output (402) for supplying illumination power to one or more light sources (403), and a power converter (404) coupled between said operating power input (401) and said illumination output (402) for converting received operating power into illumination power, which is directed outside. The power converter (404) has a control connection (405). The control device has a control data connection (406) for transmitting control data, and a controller circuit (407) coupled between said control data connection (406) and said control connection (405). The control device has a control power input (408) separate from said operating power input (401) for receiving control power to said controller circuit (407) independently of said operating power, as well as a galvanic isolation (409) between said control circuit (407) and said power converter (407). The coupling from the controller circuit (407) to said control connection (405) passes through said galvanic isolation (409).