A vehicle (2) comprises a plurality of vehicle lights (14a-k) to be matched by additional lights (8a-j) in use; respective connecting interfaces (20a-20h) associated with each of the vehicle lights (14a-k); and an electronic controller (24) for controlling supply of light-activating power to the vehicle lights (14a-k) and to the associated connecting interfaces (20a-20h). The controller (24) is configured, in a light testing mode, to supply said power to each of the vehicle lights (14a-k) and to each of the associated connecting interfaces (20a-20h) in a sequence for inspecting whether additional lights (8a-j) connected in use to the connecting interfaces (20a-20h) match the vehicle lights (14a-k). Related systems, methods and controllers are also described.