I know this is an older thread but I need some help. my dad has a 2014 sierra and I installed a kenwwod excelon double din in dash nav system. I found the harness in the kick panel. every time I connect the rca from my kenwood rear cam input to the blue and white wire in the kick panel the video to the rear view mirror cam cuts out and the green light in the mirror blinks. I get no video to either the in dash unit or the mirror. as soon as I disconnect from the blue and white wires the signal comes back to the rear view mirror??? what is causing the video signal to be lost?