I really don't know much about vehicle electrical systems so I was hoping to get a little advice. When I have my trailer hooked up to the truck all of the lights work fine on truck and trailer, but, if I put my headlights on, my dash lights come on momentarily and then go out. In reallity, what is happening is the fuse for my parking lamps blows, thus no front or rear parking lights on the truck and no running lights on the trailer. All of the other lights work fine. If the trailer isn't hooked up, no problems turning on the headlights. Where should I start looking for problems? The trailer is only two years old so I'm assuming the wiring on the trailer is all good (but I could be wrongly assuming).