Holder (2; 102; 202; 302) for light source(s) for a lighting and/or light signalling module for a motor vehicle, comprising: - a substrate (4; 104; 204, 304) of thermally conductive material, preferably of metallic material, the substrate comprising a base (8; 108; 208; 308); - at least one semiconductor light source (12; 112; 212; 312); - a power supply circuit for the light source(s) supported by the substrate; - connection means (18; 118; 218; 318) to said power supply circuit (10, 29; 110; 210; 310) of the light source(s), the connection means being electrically bridged to the light source(s) (12, 112; 212; 312) by means of surface-welded metal wires (16; 116; 216; 316); the substrate comprising at least one structure (25; 125; 225; 325) which projects from the base (8; 108; 208; 308) and which defines a receiving surface (23; 123; 223; 323) on which at least one of the light sources is arranged in thermal contact; in which the sources are high in relation to the power supply circuit to avoid any risk of shadows being cast by the latter, wherein the power supply circuit is printed on or in a board (10, 29; 110; 210; 310) of electrically insulating material disposed on the substrate (4; 104; 204; 304), the substrate (104; 204; 304) comprising two opposing faces, at least one of the two faces comprising the at least one structure (25; 104; 204; 304); 125; 225; 325; 27; 127) which projects from the base and which defines a receiving surface (23; 123; 223; 323) supporting at least one of the light sources (112; 212; 312), the substrate comprising an orifice (13a; 230; 330) connecting the two sides and arranged opposite the plate (110; 210; 310), characterized in that the two opposite faces of the substrate each support at least one of the light sources, and in that the orifice (130, 230, 330) is arranged opposite the board so as to allow electrical connection with the light source(s) on the face of the substrate opposite that on which the board is arranged. - a substrate (4; 104; 204, 304) of thermally conductive material, preferably of metallic material, the substrate comprising a base (8; 108; 208; 308); - at least one semiconductor light source (12; 112; 212; 312); - a power supply circuit for the light source(s) supported by the substrate; - connection means (18; 118; 218; 318) to said power supply circuit (10, 29; 110; 210; 310) of the light source(s), the connection means being electrically bridged to the light source(s) (12, 112; 212; 312) by means of surface-welded metal wires (16; 116; 216; 316); the substrate comprising at least one structure (25; 125; 225; 325) which projects from the base (8; 108; 208; 308) and which defines a receiving surface (23; 123; 223; 323) on which at least one of the light sources is arranged in thermal contact; in which the sources are high in relation to the power supply circuit to avoid any risk of shadows being cast by the latter, wherein the power supply circuit is printed on or in a board (10, 29; 110; 210; 310) of electrically insulating material disposed on the substrate (4; 104; 204; 304), the substrate (104; 204; 304) comprising two opposing faces, at least one of the two faces comprising the at least one structure (25; 104; 204; 304); 125; 225; 325; 27; 127) which projects from the base and which defines a receiving surface (23; 123; 223; 323) supporting at least one of the light sources (112; 212; 312), the substrate comprising an orifice (13a; 230; 330) connecting the two sides and arranged opposite the plate (110; 210; 310), characterized in that the two opposite faces of the substrate each support at least one of the light sources, and in that the orifice (130, 230, 330) is arranged opposite the board so as to allow electrical connection with the light source(s) on the face of the substrate opposite that on which the board is arranged.