So you tap into the Orange wire on the wiring harness for trailering. Then open up your hood and get into the fuse box by the hood latch. Look for the number 9 relay and pull it. Then jump the two slots that are parallel to each other. this will give the orange wire constant power.
Just don't leave your cap dome light on for weeks on end
Sorry that was for the dome light power. My bad. For brake light you will get a turn signal with any wire in the back. I believe you have to get the color wire that goes the third brake light that goes above the back window. Probably found in the kick plate.