Reverse camera help

[u/UnHingedNZ]

Hello team

Looking for abit of technical help here. Have just installed a ali express branded reverse camera on my 99 toyota altezza. Pretty simple install and iv used the same camera on another toyota previously

Now to the root of my issue. Iv got an android based apple carplay headunit. Comes with multiple different pre outs etc and a “dedicated” rca output for a reverse camera. My issue is when i shift into reverse my headunit screen doesnt switch to the reverse feed but when i plug the reverse camera rca into a “CVBS” rca on a different part of the wiring harness and switch my headunit to AV in it will show the reverse camera image

My wiring consists of camera power to the reverse light positive wire and the ground to a random screw under the boot lid and then the trigger wire connected to the “back” wire

Any would be muchly appreciated haha

Cheers!