Chosen Solution

my iphone develope a horizontal line in the bottom of the screen, the weird thing is if i max the brightness of my phone it goes away but when i turn the brightness down then lock the phone when i unlock it again it shows up. can anyone tell me whats wrong?

@khelvillanda since “i max the brightness of my phone it goes away” you may start having issues with some filtering capacitors. You can of course try a new dispaly assembly, use this guide iPhone 6 Screen Replacement. Anything past the display assembly would require somebody with knowledge about boardlevel repair, like @refectio . For now, I’d just learn to live with it by adjusting the brightness.