My 7 failed after iOS 12.3 update. Was working fine prior but after update I had slow boot and no voice memo recording. The usual audio IC failure indications. Had it repaired and sorted. also have a 7 Plus and like OP have no headphone detection but earpods and jack adapter work ok in other iPhones. Did a very quick dock port swop, still same but wonder if I did this too quick now as was rushed. No audio IC symptoms showing up and have not read anything about the link between audio iC and headphone detection though not ruling it out. anybody else got any suggestions?
I know this thread is old but Im having a black screen afterLCD and battery change. Put ipod in recovery anf itunes see's it but testore fails with error code 1600. I think the LCD connector came off whilst iPod was on! I dontvthink its a backlight issue as screen totally black. Prior to putting screen down all was good during test. It was only have lifting screen to finalise things that screen connector popped off. Please help. That LCD connector is so fiddly.