iPhone 4 proximity sensor not working after replacing BLACK GSM

"I had the same issue.

My replacement glass doesn't have ""that little piece that separates the ambient light and the prox"". So i used the idea from Simon's method but instead of using electrical tape i used the black marker, painted on the glass similarly as it done on the original Apple glass. Did it several times so no light come through painted area. After that sensor's windows on replacement glass looks almost exactly as on original glass, and proximity sensor began to work."

How do you guys usually do it, when you are doing an lcd replacement, always use the scotch tape and black marker trick, or do you first replace the screen and then test if the proximity sensor works? And then if it not works, you have to do a re-assembly again?

"I have an iphone repair store too.

I am having the same problem.

I have two different aftermarket glass supplier.

70% glass works on replacement. Some of them doesn't work. Then we use other suppliers glass or same suppliers glass. It works. We use Non working glass on another customer. It works most of the time.

It looks like software problem.

Once, none of the glasses didn't work on one of the customers iphone 4. After 4 replacement last try also didn't work. I was hopeless. I put my finger on it many times. No way. I put on my ear no way. I kept on my ear like 20 second. After 20 seconds it shot off. After that it started to working fine all the time.

Software. Software. Software.

What happens (I guess) when we replace the glass software trying to look for background reflections, brightness. Doing some statistics etc. etc.

Software. Software. Software.

Now replacing iphone 4 glass is nightmare nightmare nightmare."

"Proximity problem solved.......

I just replaced yesterday one black iphone 4 broken glass. Proximity sensor didn't work. I was going to replace glass again. Before I replace the glass I decided to do a simple restore (4.3.3).

It worked ...............

Soooo it's not a hardware problem. It is software problem.

I guess : When you restore your iphone with a new firmware it measures your glass darkness and backgroud reflections while you restoring the new firmware. It also measures all hardware components. I am sure data kept in some files. When you replace the glass, new glass darkness and reflections are usually different from previous one (sometimes). You think your glass is bad. But your new glass works on other iphones. That explains everything.

If your proximity is not working --> You can simply restore your iphone to 4.3.3 (I just tested once and it worked with custom firmware 4.3.3 created by sn0wbreeze)

I hope it works for everbody.................

I have been working on this weird thing more than 2 months."

"I just ried the foam-fix with a DIY foam-frame.

It worked perfect on an iPhone we already assumed to be lost.

My guess:

If the light sensor gets too much light, it doesn't work (o'really :).

But where does it get the light from, when you cover the front?

From the backlight!

The light from the lcd panel diffuses into the light sensor.

So if you take a little bit foam to make a frame around the sensor - just like the thing on eBay linked above

http://tinyurl.com/6w7uutc

this problem is solved.

Wow."