Originally Posted by UngaWunga
Ok, my 2011 390 has an open connector around the battery as well, but brown and white wires. They're used to power the rear turn signals. I bought a KTM wiring harness to make my own streetlegal kit. So it's not really "unused". Maybe I can piggyback on it to close a relay for the grip power. I did that on a couple of different bikes.
I installed a set of turn signals as well (SicAss). The rear turn signals plugged into an unused connector up near the ECU, leaving the other one (which is down near the bottom of the shock) still available. According to the wiring diagram, I think it is x300, which has a brown wire and a blue/yellow wire. I am pretty sure it is for auxiliary power. The brown and green wires are the ones I added to run up to the headlight area.