Chosen Solution

I just replaced the battery in my iPhone 5S. Accessing and replacing the battery was straightforward. Getting the touchscreen and display to work properly afterwords has been difficult. I lost track of how many times I connected / disconnected / reconnected the three small rectangular connectors in the upper right part of the phone. After multiple attempts I got the lines in the display to go away and the touchscreen to work properly. I have two unresolved but related issues.

  1. Un-even display backlighting brightness on the left side and near the top.
  2. Brightness of the whole display is low compared to before dis-assembling the phone. I suspect one of the three connectors is still not properly installed. I am reluctant to take the phone apart again. Just looking to confirm my suspicions.

When you originally re-assembled your phone, was the battery disconnected prior to re-connecting the LCD and Digitizer flex connectors? Sometimes this can cause the backlight circuit to fail. There is a single line (anode) going to power the backlight but 2 return lines (cathode). If the display is dim on only one side, it could be caused by a failed filter on one of the cathode lines. Of course, it could just be an improperly connected connector…sometimes they’re a pain to align correctly.