I bought a used 21 ft. car trailer the other day in CT. and towed it home. There are brakes on both Dexter axles. The truck I towed it home with does not have a brake controller, but I of course I plugged in the 7 round connector for the lights. About 30 miles into my trip there was a rest area and as normal when I pull a trailer, I pull over and just check everything out. The first thing that I noticed was that there was smoke coming from my front right wheel. I leaned in and you could smell the brakes. I felt the other three wheels and they felt warm as well. So, at this point I was a little worried. I unplugged the trailer, backed it up and put the truck in neutral. The trailer did not stop the truck, so the brakes were probably not on. I drove for another few miles and checked the wheels and they were cooler. By the time I got home they were back to normal. So, what it the world happened? The only thing that I could thinm of was that when I picked up the trailer, the light plug was corroded, so the owner had filed it down. Could that have caused a problem? Does it need to be filed down more? Would corrosion cause a short circut like this. Any ideas would be greatly appreciated.