I use https://www.neutrinoblackbox.com/ https://www.neutrinoblackbox.com/ for same with great success. I tapped my brake line electronics and the app lets me s

I use https://www.neutrinoblackbox.com/ https://www.neutrinoblackbox.com/ for same with great success. I tapped my brake line electronics and the app lets me set up the sensitivity for when decelerating brightens them up. Also a lot of other fun features you can read about on their site.