A lighting circuit assembly, in particular for lighting or signaling devices of motor vehicles, comprising: - a first electronic printed circuit board; H - a second electronic printed circuit board; - a first lighting circuit; and - a second lighting circuit, in which: - the first lighting circuit comprises a first matrix of LED lighting sources and a first network of resistor elements connected to the first matrix of LED lighting sources and configured so as to determine the driving current of the first matrix of LED lighting sources or more driving currents of respective groups of LED lighting sources of the first matrix of LED lighting sources, - the second lighting circuit comprises a second matrix of LED lighting sources and a second network of resistor elements connected to the second matrix of LED lighting sources and configured so as to determine the driving current of the second matrix of LED lighting sources or more driving currents of respective groups of LED lighting sources of the second matrix of LED lighting sources, in which the first matrix of LED lighting sources is mounted on the first electronic printed circuit board, the second matrix of LED lighting sources is mounted on the second electronic printed circuit board, wherein said first lighting circuit and second lighting circuit are configured and/or controlled so as to perform different lighting functions that are almost never simultaneously active, and consequently are configured and/or controlled such that the first matrix of LED lighting sources and the second matrix of LED lighting sources are almost never powered simultaneously, the assembly being characterized in that at least some resistor elements of the first network of resistor elements are mounted on the second electronic board and at least some resistor elements of the second network of resistor elements are mounted on the first electronic board. - a first electronic printed circuit board; H - a second electronic printed circuit board; - a first lighting circuit; and - a second lighting circuit, - the first lighting circuit comprises a first matrix of LED lighting sources and a first network of resistor elements connected to the first matrix of LED lighting sources and configured so as to determine the driving current of the first matrix of LED lighting sources or more driving currents of respective groups of LED lighting sources of the first matrix of LED lighting sources, - the second lighting circuit comprises a second matrix of LED lighting sources and a second network of resistor elements connected to the second matrix of LED lighting sources and configured so as to determine the driving current of the second matrix of LED lighting sources or more driving currents of respective groups of LED lighting sources of the second matrix of LED lighting sources, in which the first matrix of LED lighting sources is mounted on the first electronic printed circuit board, the second matrix of LED lighting sources is mounted on the second electronic printed circuit board, wherein said first lighting circuit and second lighting circuit are configured and/or controlled so as to perform different lighting functions that are almost never simultaneously active, and consequently are configured and/or controlled such that the first matrix of LED lighting sources and the second matrix of LED lighting sources are almost never powered simultaneously, the assembly being characterized in that at least some resistor elements of the first network of resistor elements are mounted on the second electronic board and at least some resistor elements of the second network of resistor elements are mounted on the first electronic board.