Left turn signal blinks fast when turned in that direction?

Was trying to hook up trailer wires for a trailer. I put new wires on the trailer, kept the lights. I went to U-Haul to get the wire for the van and was going to wire it myself. I had it at one point on the van working then hooked it to the trailer and nothing. The problem now is my left blinker blinks fast when turned in that direction. Checked mini fuses not sure about the bigger ones. Any help would be great. Thanks