Camera Trouble Shooting - step by step:
 

Does the screen recognize the car is in reverse?   
    No - Change in reverse
             Test the voltage on the trigger wire going into the unit.  It should be at least 10V.  In some cars, depending on the model, the power
             trigger is not found in the camera retain cable but rather a different one.   With a multimeter you will need to test the other wires in
             one of the other plugs. 
             Once you have located the trigger wire please send a photo so it can be added to the images below !!

    Yes but the screen only goes black 
            a) check to ensure the Yellow male RCA from the camera / power cable is connected to the female Yellow RCA of the stereo
                Make sure the camera is getting power - if it has a Purple or Red wire these will need power from the trigger wire as above
        
           
            B) Does the car have CANBUS controlling the camera?
                  - No
                        a) Test the camera is being powered. 
                        b) Test continuity of the RCA cable.
                  - Yes
                        c) Would be rare but possible wrong adapter supplied - contact with images


    Yes but  the image is poor or black from new camera or displays 16 small images.
                  Most stereos are capable of displaying NSTC, AHD, Standard Analogue, PAL etc. 
                  Depending on the firmware of your stereo you will need to adjust the camera inputs
                        There are 2 videos showing how to change the selection
                        https://www.youtube.com/watch?v=MQ3WSlAJR8Y
                        or
                        https://www.youtube.com/watch?v=x2l8Cqv0GZw
                   If your car is Diesel powered then take the earth off the camera. 

Yes but the image is poor or black from factory camera
              The stereos can only display the output coming from the camera but in some instances the image is poor. 
              This is evident mainly evident where the factory screen is low resolution.  It is akin to installing a high
              performance engine and expecting it work with E10 fuel.
              The other issue with poor resolution can come with Diesel powered engines. Diesel cars put out more
              electronic noise around the vehicle and especially the dashboard and this can effect the electronics of the
              new screen.  This may effect not only the camera but also Bluetooth as well


 

Toyota 200 Series 2007+

Re-powering the existing factory camera

To repower the factory camera you will use the supplied adapter



The black wire is to be earthed.
The other wire (green) is the power source for the camera. 
The green wire pictured below is the power source which is only on when the car is in reverse
This Green wire pictured is to be connected to the Green on the adapter and either of the Blue wires marked Back

or
This is to be connected to the power wire for the camera as well as to either or the Blue wires labeled BACK on the supplied wiring looms
And then of course you will need to program the buttons onto the stereo unit via the steering setup.

Isuzu MU-X

The Reversing Camera:
You will be have provided with a camera retention cable similar to https://aerpro.com/apviz01?src=api
One of these wires will be live when the car is in reverse.  This wire is to be connected to either one of the 2 Blue wires marked Back. This will trigger the unit so the screen knows when the car is in reverse.  If you do not have a multimeter simply put the car in reverse and try any of the 3 wires till the unit switches to reverse. Can you please advise which wire you used. 

The Yellow male RCA is connected to the Yellow female RCA for the camera on the wiring loom with the bunch of RCA cables.
 

Navara NP300:

If you car has a single camera you will need to join the wires as described on the image


 

Toyota Hilux 2015+

The reverse camera is trigger is shown below on the joined wire and is run to power the camera..


Renault Captur 2014-2016
The Reversing camera

The reversing camera can be retained by hard wiring a RCA cable and 6V power supply as pictured below

Mitsubishi Triton MN GLX-R

White to Pin3

White/Black to Pin9

Black to Pin10