Abstract: A tester for a relay comprises an enclosure, a testing circuit that includes a controller, electronic switch components, a power source, indicator LEDs, a test start switch, a relay type switch, and five electric leads each connected with one terminal of the relay. With the relay type switch set to the type of relay being tested, with power supplied to each lead, and with the test start switch actuated, the controller can set each lead to ground, in turn, and then count the number of other leads that are grounded as a result. The controller then illuminates the at least one indicator to indicate either the passing relay test or the failed relay test based on the counts measured. Once the leads connected to the relay coil are identified, cyclic testing of the relay can be performed.

Abstract: An electronic circuit tester is disclosed which is utilized for the testing and troubleshooting of the various lighting, control and signaling circuits required in the towing of a trailer, vehicle or other conveyance. The tester generally comprises an enclosure, which may be included as a part of a wiring harness connector, or separately attached to a wiring harness connector by means of electrical wiring. The testing circuit includes a plurality of input lines, logic means, and an alerting means. The testing circuits cause a distinct alert to be produced in response to each distinct test of the trailer device driving circuits of the vehicle.

Abstract: An electrical test lead includes an insulated electrical cable having a proximal end and a distal end, an electrical connector disposed at the proximal end of the cable and connected to a test instrument, and an electrically conductive magnetic probe disposed at the distal end. The probe is adapted to magnetically attach to a test point in an electrical system and to provide an electrical connection from the test point through the probe, the cable and the connector to the test instrument. Together, the test lead and the test instrument may be used as an electrical test kit. The test lead may further include an additional electrical test lead component magnetically attached, and electrically connected, to the electrically conductive magnetic probe and extending therefrom. An additional electrically conductive magnetic probe or a non-magnetic electrical connector may be disposed at the distal end of the additional electrical test lead component.