Just purchased a 5 x 8 utility trailer. Lights on the back of the trailor were not wired in, wires were hanging loose both sides. Wired lights according to instructions, pass. Side green brown, drivers side yellow brown. With that all done connected trailer harness to vehicle plug to test lights everything worked as expected, brake lights, blinkers but when I turned the parking.lights on a fuse blew. Would u have any idea what may cause this?