In the development of a vehicle component, provision may be made for a component to be tested during a test drive. Thus, the behavior of the vehicle component in the event of failure of a sensor, for example, can be tested. The aim is to enable systematic checking of a mode of operation of a vehicle component. An isolation adapter has a terminal for the vehicle component and a switching device that has a plurality of switch contacts to which a respective test circuit can be connected. An electrical connection between the terminal and at least one of the switch contacts can be produced by switching the switching device. Even during switching, there is always an electrical connection to at least one of the switch contacts. The isolation adapter may also have a display unit that mechanically detects a switching position of the switching device.