Chosen Solution
I replaced the screen on my white iPhone 4S 16GB. Now the ambient light sensor works but the proximity sensor does not. However when I take the proximity sensor out of the case housing (removing the retention clip and laying it downwards) it detects my hand or anything close by and works. The replacement screen has a filter over the sensor bar, and it has a small divider bar in it. I’ve tried the sharpie trick, placing tape and it doesn’t seem to work :( There’s also a foam pad that is already there but it didn’t seem to make it work in the first place. What is going wrong?
In the photo below, the red area is where I placed the tape over. The orange arrow is pointing to where there’s a piece of glass in the frame that seems to sit in front of the sensor circled red in the picture above.
This could be a few different things. One thing is that the glass replacement you purchase doesn’t have the same proximity sensor type paint and your proximity sensor flex is not able to go through the glass. The white screens are very finicky especially when it comes to the proximity sensor issue. Try to make sure the gasket is line up properly with the housing, lined up on the glass and not damaged so there is not light leak. Light leak is usually why the proximity sensor stops working. If all that fails, retest your old screen to see if it works on the old screen, if so, you know it’s your screen. You can then return that screen if that is the case for a replacement one that will work. Make sure the proximity sensor is also all lined up as it is very easy to be off during installation and will not work. Other thing it could be is a failing flex cable but since it works, sounds to be more like the screen itself.
You said you tried the sharpie and tape trick? If I am thinking about that correctly, it’s were you take scotch tape and put it over the glass where the sensor sits and you use a sharpie to color that in right? At the end of the day, if that trick doesnt work it has to be the glass. The glass is just not letting in the correct amount of light or it’s letting in too much and never gets triggered. I have used the tape trick a lot in the early years or 4 and 4s repairs, but didnt have to once the quality of the glass and manufacturing process was better.
I figured it out. Unfortunately it might not be of any use to anyone which is a shame. Turns out it is the logic board. I have a friends iPhone 4S that works fine in the proximity sensor area and I tested the following: The new glass/lcd on the working 4S. Sensor works fine.Proximity sensor replacement with the new glass/lcd on the working 4S. Sensor works fine.Proximity sensor replacement with the working 4S’s original screen/glass. Sensor works fine.Logic board swap into the working 4S’s chassis/proximity sensor/original screen & glass. Sensor no longer works. So I don’t know what’s wrong with the white 4S’s board but it seems it doesn’t seem to work with functioning parts. Everything else works fine, just the proximity sensor is messed up. I’ll have to use it as an iPod or something now. Thanks to all that have offered help.
