The switch box is prone to malfunctioning, basically a POS. I installed a quad view monitor from Rear View Safety, one of the best mods I have made. The monitor has the same 4 pin connections as the Thor cameras and the switch box is eliminated. You can view one camera or all three at the same time. I left the turn signal trigger wires disconnected because I use my mirrors but with all 3 cameras displayed at the same time there is no need.