Why is the white light indicator no longer turning on?

I did a housing swap, and yes every single ribbon cable is plugged in, but the white light is no longer working to indicate whether or not the controller is on. The side colors do work, but im not sure why the LED has stopped working. Not sure if maybe I messed something up with the battery when taking it apart, but it worked for months then when i took it apart to tighten a loose screw, it stopped turning on from there on.