In order to test at least one of the operating and capacitating conditions of an automotive vehicle, plural parallel circuits are included in a test circuit associated with sensors for each condition to be tested. These parallel circuits contain at least one pilot lamp and at least one switching unit. The switching unit may have simple switch contacts or may contain an electronic switching element. During normal operating conditions, the switching units are closed to provide a conductive path therethrough. During non-normal operating conditions and/or capacity conditions, the switching units open. For testing any condition, an individual test switch, which energizes each pilot lamp in the plural parallel circuits, is connected in series with the switching contacts and/or the conductive electronic switching elements of the switch units and with the pilot lamps in the plural circuits.