Patent attributes
A tow electrical tester includes a housing having a socket defining positions for at least four electrical connections between a towing vehicle and a towed vehicle, with the preferred embodiment shown having seven such socket positions. A plurality of indicator LEDs are exposed on a distal end of the housing. An electrical circuit within the housing connects each LED in a circuit branch between a common/ground socket position and one of the other socket positions. The electrical circuit includes a primary series resistor within the housing arranged in series for each LED, which protects the LED and adjusts the forward voltage across the LED. For at least some of the circuit branches, a secondary parallel resistor is added within the housing arranged in parallel with the associated primary series resistor and indicator LED, thereby increasing current draw within that branch to meet the requirements of “trailer present” detection circuits.
