What vehicle are you using to tow your boat? I have a 2006 dodge and when I hooked it up to my trailer, right side of lights would not work on trailer. But if I hooked it up to different truck all trailer lights would work. Found out on newer dodges if you have a short, you may have to have your module reset for your tow package. Cost me 155 bucks. Take a meter and check voltage at your socket on the truck. Make sure you are getting 12 volts on the appropriate pins.