Abstract: The present invention refers to a method and a device for sequentially operating light source, in particular a lighting system for signalizing a change of driving direction of a motor vehicle, comprising a plurality of light emitting diodes (LED) connected in series, said diodes can be activated in a pre-determined sequence within a required time frame t0. The method comprises activating within a required time frame (t0) a sequential operation of a plurality of LEDs, wherein the operation of the first LED in the plurality of LEDs and operation of the last LED in the plurality of LEDs is carried out within an actual time frame (t1) of operation. The method further comprises activating after lapse of a safety time frame (t2) of all LEDs (11, 12 . . . 1n) simultaneously.