A method for producing a vehicle component from a fiber-reinforced plastic, comprising the steps: - Providing at least one skin area with an inside, an outside and a receiving section arranged on the inside, the skin area being made of a fiber-reinforced, thermoplastic material, - Provision of at least one stiffening component (4, 30) with a connecting surface, wherein the stiffening component (4, 30) consists of a fiber-reinforced, thermoplastic material, - Contacting the at least one stiffening component (4, 30) and the at least one skin area so that the connecting surface lies on the receiving section, - Surface heating of a joining zone in which the connecting surface of the stiffening component (4, 30) and the receiving section are located, so that the at least one stiffening component (4, 30) and the at least one skin area are welded together, - cooling of the joining zone, - comparing a determined geometry of the combination of stiffening component (4, 30) and skin area with a predeterminable geometry, and - Renewed heating of the joining zone, deformation of the stiffening component (4, 30) and the skin area and cooling to achieve the predeterminable geometry, if the determined geometry deviates from the predeterminable geometry, - further comprising the step of placing a conductive layer on the connecting surface and / or the receiving section, - wherein the surface heating includes the application of a voltage across the conductive layer, characterized in that - the application of an electrically conductive layer includes the integration of a sensor wire which can be connected to a control unit, - Wherein the cooling comprises the step of maintaining a moderate heating of the joining zone during cooling, and - wherein the control unit controls cooling by supplying thermal power by supplying electrical power to the electrically conductive layer on the basis of a temperature determined by means of the sensor wire. - Providing at least one skin area with an inside, an outside and a receiving section arranged on the inside, the skin area being made of a fiber-reinforced, thermoplastic material, - Provision of at least one stiffening component (4, 30) with a connecting surface, wherein the stiffening component (4, 30) consists of a fiber-reinforced, thermoplastic material, - Contacting the at least one stiffening component (4, 30) and the at least one skin area so that the connecting surface lies on the receiving section, - Surface heating of a joining zone in which the connecting surface of the stiffening component (4, 30) and the receiving section are located, so that the at least one stiffening component (4, 30) and the at least one skin area are welded together, - cooling of the joining zone, - comparing a determined geometry of the combination of stiffening component (4, 30) and skin area with a predeterminable geometry, and - Renewed heating of the joining zone, deformation of the stiffening component (4, 30) and the skin area and cooling to achieve the predeterminable geometry, if the determined geometry deviates from the predeterminable geometry, - further comprising the step of placing a conductive layer on the connecting surface and / or the receiving section, - wherein the surface heating includes the application of a voltage across the conductive layer, - the application of an electrically conductive layer includes the integration of a sensor wire which can be connected to a control unit, - Wherein the cooling comprises the step of maintaining a moderate heating of the joining zone during cooling, and - wherein the control unit controls cooling by supplying thermal power by supplying electrical power to the electrically conductive layer on the basis of a temperature determined by means of the sensor wire.