Made electrical boxes to attach to back of tail light supports to hold the trailer harness/light connections.  Short box is for the side w/o the license plate bracket.  Long box is for the side with the license plate bracket.  Depending on how the license plate is mounted on the trailer, two short boxes may suffice.  Bottom cutout is designed so that the wires do not need to be disconnected to insert into the box.  Used M3x8mm machine screws and tapped the holes enough to start the screws.

Used PETG, 4 walls, 10% infill on Ender3 S1 Pro.  Water resistant, not water tight.

Remix of [https://www.printables.com/model/764091-waterproof-ip67-ip65-junction-electrical-panel-box](https://www.printables.com/model/764091-waterproof-ip67-ip65-junction-electrical-panel-box) .