Viewing the second camera:
The second or third camera is to be connected to the AUX input of the unit.
To view this is quite easy. If you are towing a caravan then you will need to turn off the Reverse detection, otherwise you will be viewing the cars camera instead of the second camera when reversing. To do this simply:
Plug the camera to the AUX input
Then from the main menu go to
Reverse detection. Turn this off.
Then when you put the vehicle into reverse it will no longer display the car camera.
Next from the Main Menu select
The press the no 2 buttons (At the top of the screen -just under where is says Media)
Select the AUX input and you will be able to see if the image is coming from the camera