I had to replace my cable and plug; the plug had some wear and I could see corrosion down in it, plus I found a cut in the cable sheath. I found exactly what I needed on Amazon (Hopkins 20146). It was about $25. I had problems, but they were self inflicted while rewiring a separate connector box. Bottom line, if I were only replacing the cable and plug it would have been a very easy color for color wire for wire swap. BTW - that is why I always tow with my heaslights on during daylight. I can see the side clearance lights. As long as I see the clearance light lit up, I know the trailer is still plugged in.
