Hooked up my boat trailer on Friday. Walked behind to quick check the lights and...NOTHING! I checked all the fuses, connectors, and other easy stuff I could think of but no luck. Called my dealer who said bring it right in. The service manager rechecked all of the easy stuff too, scratched his head, and said run it into the garage and we'll look at it right now. After two hours of reading wiring diagrams and doing circuit testing they still couldn't figure it out. On a whim they broke open a new wiring harness kit and discovered a "dummy plug" that fills an empty connector on the harness. This dummy plug doesn't just keep rain and dirt out it completes the circuits to the 7-pin and 4-flat connectors on the hitch plate. Plugged it in and everything worked. This plug is connected quite securely when it is properly installed. Since there is no way it would just fall out, they believe that the tech who originally installed the harness must not have pushed it all the way in. There was no charge and I was late but still got to go fishing. I love my Honda dealer as much as my Honda Ridgeline. Just as a precaution I wrapped some electrical tape around this connector to be double sure I don't lose it again. I think the empty connector has something to do with elecric brakes, but not sure. I don't have them on my light trailers.