Picture quality is very good. very happy

Who the blue wire is the one you can wire a relay to and use the switch. it becomes the proprietary input when activaqted with a 12 volt source.
i got my relay at the local stereo shop and it was a mini that had wires allready hooked up to it dont reacall the brand.
but the colors used were
red------12 volt positive that came from switch so the switch was used to add power to relay allowing the current to flow through the brown wire wich activated blue wire
black----neg ground
yellow---12 volt positive from the backup lights
orange-- to blue wire on pac unit
brown----to blue wire on pac unit
when the vehicle is placed in reverse the yellow wire carries the current through to the orange wire. thus activating the pac unit
if you look at a normal relay you should be able to see how the current jumps through when the relay is activated by the diagram.
now understand i am no expert i just played with the relay using a 12 battery on my work bench till i figured it out.
good luck
Jay