US Patent 9128119 Electrical circuit testing

An electronics system module includes a primary electrical circuit including input connectors and output connectors and a filter circuit connected between the primary electrical circuit and ground. The module also includes a switch element connected between the primary electrical circuit and ground. The switch element is configured to be engaged by a test connector to open the switch to disconnect the primary electrical circuit from ground. The test connector includes electrical connectors configured to connect to the input connectors and the output connectors of the primary electrical circuit. The switch element is configured to automatically close based on the test connector being disengaged from the switch element.