[CREWZIN]

I'd put it all back together and take it to the place that put the trailer hitch on. That's the place who screwed it up. Even if it was working when you left, they are the ones who worked with the wiring and even if they won't admit to doing something wrong and saying "it was working fine when you left", power to the lights just don't stop by itself and they were the last ones to mess with it. Be nice about it and if it's a reputable company, they will work to find your problem.