My (overly-ambitious) wiring plans drag on, but the end is in sight. All of the 110v wiring is done. Check. Now to finish the trailer lights.
When we purchased the trailer, the trailer lights (taillights, brake lights, turn signals) had been completely bypassed. Temporary wires dangled under the belly pan and up the outside of the tail. Not the least, the trailer brake wires were completely cut off. This arrangement (sans trailer brakes) worked for almost the whole ride home before it blew a fuse in our tow vehicle.
We had a bit of a snafu the first time I rewired the trailer lights. The night before we moved out of our warehouse, we hooked up the tow vehicle and...nothing. Since it was time to move out, I grabbed a 4-wire connector and ran some quick temp wires to the lights. Once we were back home, I tested and found out that 4 of the wires on the molded Hopkins 7-blade cable I purchased didn't have continuity. I assumed that I must have damaged it in some way during installation.
Months later, I finally got around to replacing the wiring pigtail. I went back to the same store and bought another pre-wired Hopkins 7-blade connector. I spliced it in, hooked up the tow vehicle, and... uh-oh.
The brake lights didn't work at all. No left blinker. The right blinker made the running lights on the left side of the trailer blink. Crap.
I began to doubt my sanity and worth as a human. Frustration rose. Then, I began tracing down the wiring.
Turns out the color-coded wiring I bought is very different from what I expected. On a 7-blade connector, the usual scheme that Hopkins uses for color-coding the wires is in this order, clockwise from top: brown, yellow, white, blue, green, black, with purple/red in the middle. What I got from my pre-wired (Hopkins) connector was oh-so-different: green, red, white, blue, brown, black, with yellow in the middle. Wow! I really wish I had found the chart on this page to start with; I would have known that they used a completely different color-coding scheme. It'd be nice if Hopkins would note that on their website.
It was an easy enough fix to swap the wires around and apply some colored electrical tape to avoid future confusion. Woo-hoo! The wiring checklist grows shorter...