The extra red wire with the video RCA cable is the trigger wire, normally used to switch to the rear camera video on the head unit. You may or may not need this, depending on how the head unit switches to reverse camera view. Many head units (inc. the Eonon I think) can use the data signal from the iBus or CANBus signals to do this switching, rather than a physical wire.

You'll need to figure out the best way to do this with your particular head unit and camera setup.

__________________
Wayne
2005 BMW X5 3.0d (b 02/05)
2001 BMW F650GS Dakar (b 06/01)