Hello. I am new to this forum. I am trying to install an aftermarket android head unit on my 2017 Outlander ES. I wanted to retain the OEM rearview camera. However, I found that the 8-pin factory camera harness doesn't have a reverse trigger wire. Magically when I connect this 8-pin harness to the original head unit, it triggers reverse and turns on the camera, but I don't understand how it works without a reverse trigger wire. Anyone can help? Thank you.

 

Update: I ended up T-tap the reverse light wire on the interior fuse box to the head unit. It's the pin 12 of C-418 13-pin connector. Worked well.