A Backup Camera Mystery for the ages

[juandhi]

Setup: Pioneer 4400nex on 2012 VW Passat. Replacing a an Android headunit, with which I had already installed a back up cam and was planning on using the same one for this new head unit. Backup cam had been working perfectly, with power coming from an add a fuse tap in the fuse box. Using a PAC Rp4 wiring harness in the new Headunit. With new Headunit it successfully shifts to reverse cam input via canbus every time . Problem:  it's a black screen no matter what I've tried. I'm plugged into the proper brown rca input. 

Camera: ( https://www.amazon.com/dp/B075ZPNL7J?ref=ppx_pop_mob_ap_share)

• I moved the power to the red accessory line on back of the head unit, no dice .
• Tried the cam view outside of reverse , no signal .
• I've used a multimeter to assure power is still getting to camera power cable .
• I used a noisefilter in the previous setup, tried taking that off and power directly
• I tried using a different rca cable.

Could it have shorted  during pioneer install? Or ground come loose? Is there anything about the specifications that would prevent it from working with newer pioneers ? I'm not awesome with the multimeter, could just measure the voltage coming out of the barrel. 

Anything about my wiring setup sound like it would cause issues ? Triggering by the canbus is fine correct? this camera was working perfectly fine on my old android headunit right before i installed the pioneer. 

Thanks for all the help guys !