The invention relates to a light device for a motor vehicle, comprising a matrix light source having a matrix of elementary light sources with an electroluminescent semiconductor element. Each elementary light source has an emitting surface that is less than or equal to 0.2 mm2. The measures proposed by the invention allow such a matrix light source to be powered without any risk of damage due to overheating of the semiconductive junctions of the elementary light sources that make up the light source.