Over the past few weeks I noticed that the lights on my trailer had been going out, one by one. First the right front corner light went dark. Then the left rear taillight started flickering before it went out completely. I thought it was weird because just a few months ago I had rewired and re-lit the trailer with one of those (admittedly cheap) LED trailer light kits off of Amazon.
After cleaning the grounds for the 3rd time and replacing the lights without success, I started cutting into the wiring. That's when I found all of this corrosion hiding under the insulation:
What's scary is that segment is from the MIDDLE of an unbroken 7' run of wire with no splices, connectors, or anything in the vicinity. When I bent it back to see what was going on, all of the corrosion fell out of the insulation and revealed that there was NO WIRE left inside the sheathing:
Regardless of how cheap the wire must have been, I was shocked that corrosion could spread that quickly down such a long run of wire. That was until I took a look at the extra bundle of trailer wire that I had from a second kit that I had in my garage and noticed that there is a noticeable air gap between the insulation and the wiring:
It turns out that moisture had gotten in from a damaged connector and spread through this gap between the wire and the insulation. Within a few months it got so bad that there was literally no copper wire left. Strangely, the wires coming out of the lights themselves were of a different variety (and gauge) that thankfully showed no signs of corrosion.
So now my trailer has been re-wired with automotive speaker wire from my electrical kit. All of the colors are wrong now but at least I won't have to worry about this nonsense ever again. My advice is that if you ever get one of those light kits, check the wire bundle and make sure it isn't the same cheap crap that I bought. And if it is, don't use it.