(JP10094191-A)      The fault detection apparatus has a power supply changeover switch with a generator (3), a battery (11), and an electrical load. A switch controller switches on a changeover signal should it be necessary to supply the load with electrical power. A changeover switch (25) joins the battery to the generator in one position when the changeover signal is switched off and the load to the generator in the other position when the changeover signal is switched on.    An output voltage controller (5) interrupts the generator action for a certain time when the changeover signal is switched on. A detection device (30) determines that the switch is faulty if the generator voltage is higher than a certain value when a certain time has passed that is shorter than the changeover period since the switch-on of the changeover signal.    USE -   For high load vehicle systems, such as heaters and defrosters.    ADVANTAGE -   A simple procedure is used to determine faults.    (US5936314-A)      The fault detection apparatus has a power supply changeover switch with a generator (3), a battery (11), and an electrical load. A switch controller switches on a changeover signal should it be necessary to supply the load with electrical power. A changeover switch (25) joins the battery to the generator in one position when the changeover signal is switched off and the load to the generator in the other position when the changeover signal is switched on.    An output voltage controller (5) interrupts the generator action for a certain time when the changeover signal is switched on. A detection device (30) determines that the switch is faulty if the generator voltage is higher than a certain value when a certain time has passed that is shorter than the changeover period since the switch-on of the changeover signal.    USE -   For high load vehicle systems, such as heaters and defrosters.    ADVANTAGE -   A simple procedure is used to determine faults.    (DE19741194-C2)      The fault detection apparatus has a power supply changeover switch with a generator (3), a battery (11), and an electrical load. A switch controller switches on a changeover signal should it be necessary to supply the load with electrical power. A changeover switch (25) joins the battery to the generator in one position when the changeover signal is switched off and the load to the generator in the other position when the changeover signal is switched on.    An output voltage controller (5) interrupts the generator action for a certain time when the changeover signal is switched on. A detection device (30) determines that the switch is faulty if the generator voltage is higher than a certain value when a certain time has passed that is shorter than the changeover period since the switch-on of the changeover signal.    USE -   For high load vehicle systems, such as heaters and defrosters.    ADVANTAGE -   A simple procedure is used to determine faults.