Don't feel bad, I once had to replace this cable and tried to do it myself, but the colors on the new cable didn't match up with the colors on the trailer. So the brown wire from the trailer may have been for the license plate light, but the brown trailer on the plug was for your turn signal or something. I paid a guy on the side from Camping World to come out and help me figure it out and he spent over an hour with trial and error figuring out which went to which. It was a nightmare...especially since it was 100 degrees out.