iPhone 6S rear LED flash not working

I Dropped shattered my phone spectacularly, so much so that the rear housing bent a bit and that the screen shattered. So I purchased a new screen and I was fortunate to have a rear housing from another dead 6S. Everything was working perfectly before the fall, I transplanted the logic board, speaker, battery and power flex from the smashed case, to the straight one with almost no issues, data is there, everything working fine except the flash will not respond at all, whether I use the flash light function or camera. The camera works properly as well.

Thinking that taking the flex from the smashed phone (even though it worked in the smashed case) would resolve the issue. But no luck.

Please help! I had no idea I depended on the flash this much