[Easy Rider]

Are the wires swapped in error in the either trailer side plug or the harness side plug? Appears the wires coming into and out of the module are correct color codes for left and right turn (left yellow/right green).

They have to be swapped somewhere.
Do you have a wiring diagram of the trailer side ?
I assume that the square connectors have a "key" for proper alignment ?
Was the input connector for the module already on the bike......or did you install that too ??
The transposition could be all the way back there.

 

[Easy Rider]

Yes, I would think that switching the wires in the trailer would be the best option.

BUT I personally would not be satisfied with that "fix".
It would be really nice if you could find another owner with a working setup so you could plug your trailer into his bike and vice-versa to get a better idea of what exactly is wrong.

If the CANBUS controls the lights, the whole thing becomes more complicated.