The power wire is probably yellow in color, and the ignition hot (ignition switched) wire could be yellow with a brown stripe. This color scheme might NOT be same on your car, as BMW could change the colors from country to country.

I agree with your diagram for power for the Video Module and for the camera. The camera can be fed directly from the switched wire.


You said that you purchased the small relay from Radio Shack. Is it the one I mentioned? Because it is the one that you want to use for the trigger wire, not the big automotive relay.

Your Video module - does it require a (-) applied to trigger wire or a (+)?

Do not use the reverse light for the trigger wire, you will get flickering of the screen.



Let's do one thing at a time:

Do you have a VoltMeter? Can you find a switched power for the camera first? find the power for camera first, lets make sure the camera is working, and then move to next step.