How to connect the camera in Canbus vehicles
Depending on the vehicle you may or may not have a constant 12V power source form the tail lights. Although initially 12V some CANBUS vehicles will drop voltage over the next few minutes.
The theory on cabling is quite simple
1) Once the unit is working put the car in reverse.
a) if the screen goes black then the unit is getting a reverse signal from the CANBUS module. This Blue wire will now be live when the car is in reverse. Simply tap into this wire (not cutting it) and use this as a power supply for the camera
Depending on the camera you can connect the red wire (next to the RCA) and this will provide power to the back of the vehicle
b) if the screen does not go black then you will need to connect the camera to the reverse lights and then supply 12V from the reverse lights to the unit. This 12V power from the back of the unit is carried through the red wire next to the RCA and is connected to the same Blue wire as above which will need to be cut as you should not put 12V back into the CANBUS module