Motor vehicle with a multiple voltage on-board electrical wiring system and associated method

The motor vehicle comprises an electrical system (1), which has a low voltage network (2) with a primary voltage having an electrical energy storage unit (4) and a high voltage network (3) with a secondary voltage having another electrical energy storage unit (5). The secondary voltage is higher than the primary voltage. The secondary energy storage unit is divided into a partial energy storage unit (6) connected in parallel to the former electrical energy storage unit and another partial energy storage unit (9) connected in series to the former partial energy storage unit. An independent claim is included for a method for operating a comfort function realizing a consumer in a motor vehicle.