Have a 2013 cadillac xts my left rear signal is out and right tail light also my back up camera. Along with that my touch screen isnt responding to touch its stuck on the options screen and also my dome light switch doesnt work but all individual lights do work( lights dont come on when doors open on door option) ive replaced many parts to try and fix this issue including tail light module bulbs .Please help as this is now a traffic law problem not having proper lights . My friend is a cadillac mechanic and is doing the work on my car and is stumped.