I've had this 3GS for nearly three years now, and just recently (last few months) it has started to vibrate briefly (under 1 second) with no alerts or other indication onscreen as to why it's vibrating.

It happens a few times a day now, even after a reboot of the phone.

Has anyone else seen this behavior, or are there suggestions for things I can try to resolve it without repairing the hardware? In other words, yes, I realize it's probably a hardware issue, but is there a possibility it is software or can be resolved without repairing the hardware?

I used to keep in on vibrate 100% of the time, and recently have switched to letting it ring as my belt case broke and I don't feel it vibrate in my pocket.

  • Waiting for the next iPhone, so I don't really want to spend money on this one unless I have no other option...
    – Adam Davis
    Commented Jul 10, 2012 at 15:45
  • I'd say it probably is an app and not a hardware problem. It doesn't necessarily show something on screen, but might just add a badge to the app icon for example.
    – Gerry
    Commented Jul 10, 2012 at 15:47
  • @Gerry Hmm, interesting! I'll keep track of the badges and see if that's it.
    – Adam Davis
    Commented Jul 10, 2012 at 15:51
  • Does it vibrate when the the ringer is on? On my phone, there is an alert set for email, which has a vibration like you described when it's switched to silent. I agree, it would make sense if it was an app, but I've never seen an app that vibrates when the switch is set to ring. Commented Jul 10, 2012 at 17:04

2 Answers 2


When I worked at the Apple Store we had 3G and 3GS models come in every so often where their iPhone would vibrate without cause, sometimes the problem could be recreated by squeezing the top left hand corner (Pressing in on the front and back of the case) of the phone. As shown in this video:


It doesn't always show the vibrate on off icon when it happens.

We noticed it happened more with people who had 3G and 3GS phones that were older. It is a common enough issue that if you google search iPhone 3g vibrating randomly, you'll get quite a few hits.

When we had this issue, it was usually the vibrate motor going bad or having issues, a lot of time it was because people dropped their iPhones a lot and we could tell because the corners we scratched up, but it wasn't always the case. If you are under warranty, they will replace it. If not, they can replace your iPhone for a price, usually 200 dollars. There was no software fix available from Apple. We just had to simply repair the iPhone. Restoring/Updating the iPhone didn't help either. It was purely a hardware issue. There might be guides on replacing the motors in the device since it is easy to open up the devices but do that on your on discretion if its possible.

Personally, I would just hold off until a new iPhone comes out and just buy it if you want to. Unless the issue gets to the point to where it is constantly vibrating for minutes at a time, which I have also seen happen during my time at Apple, then see if you can get them to replace it. It vibrating every once in a while won't cause issues but it vibrating constantly can deplete battery life quicker than normal.

Now, it could also be an app that is just updating its badge and your not realizing it. Every time I have seen it though it was because of the vibration motor.

I hope that this information helps you out.


I had the same problem for over 2 months. My Mobile Shoppee friend used a pin to clean both sides of the Ring/Silent switch. After removing a lot of dirt the random vibrations have stopped. The culprit may be dirt accumulated on both sides of Ring/Silent switch. Carefully clean the switch with a pin if it appears to be impeded.

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