Abstract: A diagnostic device for testing a false warp stop in an industrial loom caused by a failing or offending drop wire. The device provides a connector that is operably engaged with the warp bars of an industrial loom. When a drop wire becomes worn or pliable and bridges the warp bar to stop the loom, the connector assists to create a circuit that includes the affected warp bar, a power source, a rectifier and an indicator device. The indicator device is activated by completion of the circuit and remains actuated even after the loom is restarted. The apparatus is thus effective to help locate a failing drop wire as opposed to a drop wire that has fallen due to a slack or broken warp thread.