Detection of the partial and/or total failure of a group of light sources on a vehicle

Electric power supply device for the light sources of a motor vehicle, wherein the device comprises a plurality of means for the control of the electric power supply of at least one light source respectively,

• wherein the control means each comprise diagnostic means which are configured to deliver a diagnostic signal for said light source,
• wherein the device comprises a processing unit for the diagnostic signals delivered by the plurality of control means, wherein the processing unit is configured to deliver, as a function of said diagnostic signals, a detection signal for the partial failure of light sources supplied by one of the control means, and/or a detection signal for the total failure of light sources supplied by each of the control means.