The mounting component (2) includes a module rack (4), on which components (6, 10) of a vehicle electrical system have been mounted beforehand, and is intended for installation in the motor vehicle (18) together with the previously mounted components (6, 10). At least one additional module of the vehicle electrical system (11) that extends beyond the spatial limit of the module rack (4) is connected by prior assembly with the components (6, 10) arranged on the module rack (4). The module rack (4) also serves as a self-contained transportation base for both the pre-assembled components (6, 10) and the additional electrical system module (11). This configuration enables a high degree of pre-assembly and thus also simplifies final assembly.