Proposed is a device for monitoring the operation of an electric/electronic switch controlled by a control circuit, its in-circuit consumers, its control and its connectors. The device is characterized by the fact that at least one logic circuit (5) is connected in parallel with the output stage (3) so that the input-terminal potential (UE), the output-stage (3) output-terminal potential (UA) and a reference potential (Uref) can be applied to the logic circuit. The circuit can differentiate with certainty between the fault conditions overload/short to plus, drop in load and short to earth, and diagnose correct operation of the output stage. Faults (implausible events) in the output stage, the consumer (R), the control unit or its connectors are stored by means of an encoder (7) in an intermediate store (9) which can be read out on interrogation by the control circuit (νC) into a store (11) from where they are passed to an interface (P4) with the control circuit. In this way, faults can be attributed to a particular output stage and easily identified. A cut-out switch protects the output stage from overload. The cut-out switch can also switch out output stages at defined points in time, e.g. during the initialization phase.