I HIGHLY recommend you install an isolation kit for trailer wiring. Your bike is already a 5 wire system the same as the Mini-Mate camper. I have a Mini-Mate. I do my own wiring on my bike so I made an isolation kit from parts. But for your situation I recommend you order the Isolator kit and Universal harness (
p/n 07660 & 07663) from Electrical Connection as listed
HERE. You don't need the converter kit since, as I said, you already have a 5 wire system.
***DO NOT JUST WIRE THE TRAILER CONNECTOR DIRECTLY TO THE BIKE FACTORY WIRING*** Also, don't allow your installer to use those blue crimp connectors that are cheap and easy to connect wires. They are prone to corrode on a bike especially. I suggest soldered quick connects or other sealed weather proofed connections.
I know the new Mini-Mate campers have LED lights so load would not be an issue so much as simply the addition of unknown problems to the bike should a problem in the trailer happen. I don't know if you have one of these newer campers or have an older model that still has the regular lights. I have a 2008 model that has the regular lights (not LED). Had this happen to me on my Gold Wing pulling a Time Out camper, a problem in the way the camper was wired to the bike by the former owner caused failure of a major factory relay in the electrical system and I needed to then re-wire part of the factory harness to repair. I added an isolation kit and never had another problem again. That is the biggest reason I recommend an isolated kit for any added lighting anywhere on the bike. Also, an isolation kit will enable all lighting to be brighter (also my experience) since power is not drawn from the factory light wires but instead directly from the battery.
There are a few places to get an isolation kit for trailer wiring if you look around the web. This is where I recommend. There is also a thread (sticky) on this Trailer forum that speaks on this set up.
EDIT: just noticed you mention that the trailer is wired with a 4 pin plug. These campers come from the factory with a 5 pin plug so the previous owner must have hacked it to rewire for 4 pins. I hate that when that happens. ALL bikes are native to a 5 pin system! Anyway, in your case you can go 2 ways with this. 1. Get the converter listed at EC for the isolation harness. or 2. Have the camper rewired the way it was originally, with the 5 wire set up. The exact same happened with my camper. The previous owner had hacked the wiring on the camper because he didn't understand 5 wire systems. He had also hacked his GL1100 Gold Wing to be 4 wire so there was a lot of extra converting going on that didn't need to. Anyway, I rewired my camper back to factory spec and now have a 5 wire system (native to both the bike and camper). The way you can tell the difference between 4 wire and 5 wire (at least if it's supposed to be one way or another) is if there are separate turn signal lights from the brake lights. Sometimes when a 5 wire trailer is converted to 4 wire the turn signals (which are amber on my camper) are disconnected and not used or are spliced into the running lights (not so common). So you will have to determine which way you want to go. It's less $$$ and more reliable to convert back to the factory configuration of 5 wire IMO.
