Rear brake light:
Super easy to do... but not obvious!
When you pop the right rear fairing off you find this:
Looks simple right? Looks like you should be able to plug your brake switch into that brown/white connector and be good to go? NOPE. If you connect that brown and white wire you get to locate your fuses and replace the one that says "headlight"
For your brake light to come on you actually want to connect the green/white wire to the white wire with your switch
Since the green wire doesn't go to anything on the XCW I just cut it off and then put a female barrel connector. Same for the white that goes to that secondary plug.. cut it off and put a barrel on it too.
Here's the pressure switch I used:
Super easy to install.. you just replace the banjo bolt for the rear brake with this pressure switch
and then I routed the wire forward and around instead of up the rear subframe just to give it more clearance from exhaust heat
...and then simply plug into the green/white & white. Doesn't matter which way.. you are just closing the circuit when you stop on the brake (which puts pressure on the pressure switch).