A motor vehicle includes a high-voltage source for supplying consumers of a high-voltage on-board power supply system with electrical energy, an electrical separating device for separating the high-voltage source from the high-voltage on-board power supply system and a signal emission device for indicating the connection state between the high-voltage source and the onboard high-voltage power supply system. The signal emission device is activated for emission of a signal when the high-voltage source is separated from the onboard high-voltage power supply system, and is deactivated when the high-voltage source is connected to the onboard high-voltage power supply system. A non-activated signal emission device indicates a live state of the high-voltage on-board power supply system, thereby ensuring that a safe state of the onboard high-voltage power supply system is not falsely signaled in the event of a failure of the signal emission device, thereby eliminating risk to service personnel.