Help How do the 4 capacitive buttons light up?

[Palmetto Fellow]

My 4 capacitive buttons at the bottom are not always lighting up. I can turn on the screen 20 times in a row, and they will light up. Then, I wait a moment, and turn the screen on, and they don't light up. I can then turn the screen off and on 20 times in a row and they won't come on. If the buttons aren't lit, and I am scrolling through the screens, they will sometimes just come on at random.

So I was wondering what lights them up? Is it the main board on the phone itself? Does the screen do it?

 

[Mikestony]

My 4 capacitive buttons at the bottom are not always lighting up. I can turn on the screen 20 times in a row, and they will light up. Then, I wait a moment, and turn the screen on, and they don't light up. I can then turn the screen off and on 20 times in a row and they won't come on. If the buttons aren't lit, and I am scrolling through the screens, they will sometimes just come on at random.

So I was wondering what lights them up? Is it the main board on the phone itself? Does the screen do it?

I believe the proximity sensor senses the amount of ambient light available and tells the buttons to light up or not...sometimes a screen protector and/or cover will interfere with the sensor..located by left bottom of ear speaker...
Maybe when you are turning off/on screen, the light is detected differently when you move the phone slightly?
Try it in the complete dark and see what happens....
That's the best answer I can think of at the moment

 

[Palmetto Fellow]

I did some more testing today and I think you're right. Holding the phone slightly differently causes the light to hit it differently, and thus, the buttons aren't lit up at times.

I did notice that the phone angle did sometimes have an effect, but I thought that effect was from gravity...and maybe a loose connection internally or something.