The invention relates to a sub-assembly for a searchlight signal comprising three distinct light emitting diodes and an interface module for connecting the three diodes to a controller. The interface module comprises: a light input adapted to receive a signal for feeding a light emitting diode, a first relay having an active position and an inactive position, and a second relay having an active position and an inactive position, such that: when the second relay and the first relay are in the inactive position, the light input is fed to a first LED, when the first relay is in the active position, the light input is fed to a second LED, and when the second relay is in the active position, the light input is fed to a third LED.