Back up Cam in OEM Tuner- Input dead?

[IFLYTBM]

Anyone have any ideas...I got the truck back from a local shop, searching for a rampant battery draw. The shop was baffled by the updates and additions so common to this community. They couldn't properly reconnect the wiring as I had done when it was brought it in. So I left with the most rudimentary NAV screen ever. A few swapped modular plug hookups and it was almost 100%-but...the back up camera is not functioning.

The A/V input on the OEM tuner module works as evidenced by the headrest communicating with the NAV screen-everything functions including audio, but no the camera. I even tried a portable DVD player as an input and the screen wont display or play audio??

When placed in Reverse, the relay fires, the input switches to a blank screen. So I've tested the camera on another and seperate display-nothing. and I;ve swapped the A/V (Headrest input) to the CAM input while in Reverse-nothing...its as if both the camera and the input have been killed and I'm not getting anywhere.

Nothing changed in the pinouts, they didn't know what they were doing so they disconnected everything and in their defense this did happen once before following a series of flat batteries (darn FSR), but it eventually came back to life on its own 3 days later-same symptoms then as now, but I'm X? days into this and hours of troubleshooting in and out of the truck. Has anyone ever heard of just this input dying???

[FULANITO]

It happened to me a couple of times check the fuses and try resetting by disconecting the battery for at least 30 minutes if you haven't already done so!!!
Good luck!!!

[IFLYTBM]

Good thought- The battery disconnection, the Tuner disconnection, and a general try for a systems reset was the first thing I went for. Fuses show continuity on the meter.

The camera is secondary, i can bench test or replace that- its the input on the tuner module that has got me worrying- it doesn't want to accept a video signal- from anything.

Any other thoughts- Anyone?

[IFLYTBM]

Working again! Spent another hour retracing connections and I think the issue may have been in the grounding relay where the camera gets power-but that does not explain why the tuner module wouldn't accept a different source, would it? I did not find anything conclusive, just a lot of time spent doing it all over again. All this because a non OEM shop 'eliminated' by disconnecting the 'aftermarket' items.

I guess bottom line is, sometimes these things are flaky. Good luck if you have the problem