DAsaita back up camera

Hi all, yes I know there is a bunch of threads on this but I cant seem to find a clear solution.
I have a 2008 tundra with oem back up camera. Previous owner had installed the dasaita head unit but back up camera has never worked since he tells me. I would like to figure it out as I find the camera super useful.
Only had this truck a week. Bear with me.

 

Probably going to need more info and pics, unless there is a known issue. Is it possible the camera is not hooked up?

 

It is all hooked up, somewhere I read something about the reverse not being connected to the canbus on 2008 so it may need a wire to reverse lights to recognize reverse but I’m hoping someone has had the same issues and maybe it’s a simple thing? Not likely )