I do not have mine on my 2015 Vegas wiring complete. On my plug only the lights and brake lights are wired. There is a blue wire for the brake controller; however, it is in a wire harness just rolled up and stowed behind the tow receiver. To finish wiring for a brake controller that blue wire would have to be extended to the front and 12VDC and ground would have to be added to the plug.
And there is NO brake controller plug stowed under the dash anywhere. The brake controller power and ground would also have to be wired in.
Ed & Bev Felker
Retired USAF Col and retired Nurse
Traveling with Lily & Bella ('Teddy Bear' breed)
2015 Vegas 24.1 (E-350)