I just installed a stay n play duo brake system in my 2008 Honda CRV
Easy to install and seems to work great. SMI tech was very helpful as well as their video. The tech support told me that the blue wire on the plug on the coach would work as a dedicated line to operate a signal for the LED light that would show when the brake was activated. Of course the brake switch on the Honda was connected to the blue line so when the brake light came on that would send a signal through the blue line up to the cab so it could illuminate the light.
Hope this explains what I did for my 2013 Georgetown XL 378.