Our old Class A rear camera was great when I was hitching a trailer up but with the rear camera being up so high on the back of the Seneca and then add the "check your surroundings" warning across the bottom of the video screen, its pretty much useless using it to line up a ball to the coupler.....and have the DW direct me usually lead to an argument
Today I added an adjustable eyeball camera right above the license plate. Used a 50' video cable that also has a 12v supply wire to the front and fished it up into the cab and behind the dash. Opened up the dash and started sorting through all the rats nest and found the power supply/trigger wire cable from the factory installed camera control box. I used a "Intelligent Car Video Switcher 3-way Input 1-way output for the car camera" unit from Amazon to do the switching but there is one problem with these and all the others that I could find, when the original rear camera comes on, it it will always default back to the main rear camera and I need to be in reverse when using the hitch camera. The way around this was by using a push button latch switch that has both a N/O and N/C positions. I made up a harness and wired it through the switch so when the switch is off everything runs through the factory camera setup. When you turn the switch on, it cuts power to the factory camera control box and triggers the "Intelligent" switcher and switches the video source to the head unit to the hitch camera. Then when you turn the switch off, it reverts back to normal. Works like a charm!