The connecting cable that came with the trailer was more than long enough so I ended up shortening it by a foot or so. I tapped into Red Dog’s wiring system and connected wires for tail lights, turn signals, and brake lights plus a ground wire. The factory furnished several solder-less connectors for this but I don’t trust those and elected to solder them instead.
I ran a separate power feed with its own fuse directly off the battery that feeds an auxiliary power outlet inside the trailer. This should prove to be useful as a point to recharge cell phones, computers, or power up any 12 volt device needed. One of the cool things the factory did was install an interior light inside the trailer. It's one of those touch-type LED lamps and puts out plenty of light. If you've ever fumbled around in the dark looking for something inside your gear you'll appreciate this feature.
While I was poking around locating various wires for the lights I came across a plug socket and corresponding wire that was unplugged. There was nothing about it in the manual that I could easily find so I left it unplugged and queried the members of the Modern Vespa Forum. Turns out it’s used to reset the code for the remote saddle unlocking system and if I’d plugged it in I’d have lost the feature. Somehow you’d think the factory would have tagged it with a warning note… Duh…
In the end the lights all work great and it’s hard to imagine another driver not seeing Red Dog at night, even in bad weather.
So that’s it, time to continue with weatherization of the remaining plugs, etc. Fun, fun!