Chosen Solution

So I recently replaced my iPhone 8 Plus front camera flex cable. Scince the previous one had ripped off. But afte installing the camera only the speaker works and when connected the back camera shuts off as well. But if I disconnect the front camera the back starts working again so I have no clue what going on. Unless it’s a faulty flex. But the flex has no damage on it whatsoever so I’m not sure. Appreciate any help

Check the front camera connector on the board for damage. Where did you purchase the flex assembly? I have seen this issue with some aftermarket parts for the 8 plus. It would be a good idea to purchase another one from a reputable supplier to rule out a parts issue.