Reverse Trigger Wire

[Sam Jam]

  I have bought an after market android head unit.  I also bought the harness that supports OEM reverse camera.  The head unit has a camera app which I can select to see the rear camera.  As soon as I put the car in reverse is the camera is powered up?  Does the reverse trigger wire just automatically display the camera?  - so that would mean as long as I am in reverse the camera is working and if I select it on the app it should show the image.

  I am currently not getting an image.  Just trying to work out if it's a settings issue or the reverse wire trigger that's needed.

 

Thanks for any help.

 

Estima 2010 - Petrol.

Edited June 15 by Sam Jam
car make model added

[JohnGW]

Are trying to use the original Toyota Estima camera, these generally do not work with 3rd party head units although I guess some better models might compared to lower cost Chinese units.

[Sam Jam]

Thanks for the reply.  So it would appear that the reverse selector was somehow switching power to the rear camera (turns out there was a module to reduce power to 6v) .  I tested it with a monitor with rca input and the head unit removed.  So for me the head unit was not supplying power to the camera (it was not the original head unit).  Anyway all working now.  Although it's a very grainy picture as expected but saved me the hassle of wiring in a new camera.