The NORMAL install on Rearview with side Cameras is this----The dash monitor electronics has a relay diode system internal that when the left or right turn signals engage, it sees this 12 volt signal and once it sees this it turns on the appropriate camera as long as it sees this pulsed 12 volt signal. Electronically, it KNOWS to keep the power to each camera ON continously and ignore the constat flash of 12 volt on and off. IF you have the original back up system, that did not have left and Right Camera capability, you cannot make the system work correctly. Doug