iPhone 3Gs Proximity Sensor Not Working (Earpiece Is Working)

Discussion in 'iPhone Tips, Help and Troubleshooting' started by adam8281, Jul 29, 2010.

  1. adam8281 macrumors newbie

    Jul 29, 2010
    I recently opened my iPhone 3Gs to replace the screen and digitizer. Soon after, I realized that the proximity sensor was not working - the screen would remain on and active during calls while I held the phone to my face.

    My initial thought was that the problem must be something other than the proximity sensor cable, since this same cable controls the earpiece, and my earpiece works just fine.

    I thought the problem might be that the aftermarket replacement screen was too dark over the proximity sensor, so I opened the phone back up and used a razor blade to scrape the inside of the screen above the proximity sensor to lighten it. That did not work, however, and the proximity sensor is still broken.

    Does anyone have any thoughts on what the problem could be? Is it possible that I've damaged the proximity sensor/earpiece speaker, but in such a way that it only affects the proximity sensor while leaving the earpiece functioning? Do you think my next diagnostic step should be replace the proximity sensor/earpiece cable, or is there something else I should try first? Could it be a software issue? Thanks!
  2. adam8281 thread starter macrumors newbie

    Jul 29, 2010
    well, i've bought a new proximity sensor cable for $4 on eBay. Hopefully that'll fix things.
  3. adam8281 thread starter macrumors newbie

    Jul 29, 2010
    OK, I replaced the earpiece/proximity sensor cable (the #3 cable), and the problem remains. The earpiece works just fine, but the proximity sensor doesn't work.

    Anyone have any advice on what to try next? I'm guessing that since the cable didn't fix it, the problem is probably on the logic board, perhaps the "clip" that the #3 cable goes into?
  4. Reddddsrum macrumors newbie

    Sep 3, 2010
    iPhone 3Gs Proximity Sensor Not Working (Earpiece Is Working)

    Im having the same exact issue..I replaced the proximity #3 sensor and the problem is still persisting....The headset speaker works but the sensors dont. I tried updating to the latest os but that didnt fix the problem either.
  5. johndallas999 macrumors 6502a


    Oct 9, 2008
    I'm having the same problem. Did you guys find a fix? I was thinking about spending 4.00 on a new cable but both of you said it didn't fix it.
  6. chargit macrumors 6502a


    Jan 17, 2010
    Evansville, In
    well more than likely you didnt take the adhesive off of the frame where it covers the proximity light sensor! maybe a DYI Repair is not your cup of tea!

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