Abstract: A test cable device comprising a main cable with a standard trailer connector; at least seven inner wires in the main cable, the first ends of each inner wire extending from the first end of the main cable, the first inner wire being a ground wire; a first clamp operatively connected to the first end of the first inner wire; and a second clamp operatively connected to each of the first ends of the second, third, fourth, and fifth inner wires; wherein the first ends of the sixth and seventh inner wires are operatively connected to a first flasher relay, the first flasher relay can be operatively connected to a port of a relay unit; wherein the device can be operatively connected to a power source via the first and second clamp, power is directed through the device and to the trailer via the trailer connector.