Abstract: A testing installation for electric circuits of a motor vehicle, in which input signals are converted in a common central control unit into output signals for switching different loads; the testing installation includes a generator which produces signals at least similar to the output signals of the control unit and feeds the same cyclically to the loads or the switches thereof; as a result, only the critical portion of the electric circuits is switched and the functioning ability thereof is tested optically or acoustically without further auxiliary means.

Abstract: An electrical installation for triggering switching functions in motor vehicles, with a central unit producing from input signals, coordinated output signals to switch load switches, and a redundancy unit; the input, respectively, output signals are thereby combined into groups of mutually similar switching functions and the redundancy unit is so connected that it prepares or readies for each group an output signal for the switching function which, in comparison with the other switching functions of the corresponding group, possesses the highest priority.