Camper shell electrical work

[u/TheBuddbrown]

Hello, I got this camper shell a little while back, and I’ve been building or buying parts for it. It’s ready at this point to take anywhere, but I just want to get this third brake light fixed, and I don’t know a thing about how to get it done. Any suggestions would help. Thanks.

[u/Individual-Nebula927]

With caps, best practice is usually to start over entirely rather than figure out how the last guy wired it.

All you need is a pigtail for a 4 pin trailer plug, and then wire the brake light to that (so if you remove the cap, you can disconnect the wiring from the truck). Then either plug an extension harness into the trailer plug, or tap the wires on the truck before the plug and run them up to the cap. Then plug in.