iPhone 5 screen dims by itself..

Nothing. Apple has still not come out with an update to fix this. What you can do is tweet it out to apple and call to report it.

so can you please guide me how to tweet them and what num# should i call!? cause i am new in Apple world and i dont know anything,i even regret changing from Android to apple after i face this problem with my first Iphone,i was always complaining about the bad batteries in Android phones now i am facing a softward problem :S

Thanks

Not sure where you are located: http://support.apple.com/kb/he57

The problem is people are not reporting it to apple so they are not fixing it. Report it.

It is happening on Iphone 4s too.

This happens occationaly to me when I am running around town.

I have tried hitting top button once... wait a couple seconds then hit it again.. It "wakes" it all up again.

-David

It's been happening to my iPhone 5 since a couple of weeks after I bought it

Same problem here with iPhone 5. Except mine does nothing when slider changed. Only way I found to fix was turn off/on. Apple has already tried all the settings and also replaced my phone. At times I've had it dim so much it looked off and I'd guess it was showing less than 5% of the brightness since had to put eye right next to it to see anything.

Has this ever happened to someone indoors? I wonder if its a heat related thing as seems to do when phone usage is high or car temp goes up etc. a power off always fixes though

As far as auto brightness, well I've reported that since iPhone 3. I've had them all and NONE OF THEM HAVE EVER WORKED. I've reported this numerous times. Never any solution

I may have found a new step to try on my 5. If you have the flashlight app from "Apps From Outter Space" - the green icon with yellow flashlight - go to the settings there. Inside there is a "change hardware brightness" setting, as well as "turn display off" with subsequent "after 5 minutes, 10 minutes, etc". I thought about dupilcating the issue to isolate it, and remembered it also happens (the dimming issue) going into or out of that flashlight app. My wife has a 4S with same said flashlight app and her phone has the same auto dim issue. So I checked the settings in her flashlight app, and they were set exactly like mine: Turn Display off after 1 hour, and Change Hardware Brightness was checked.

My hypothesis, based on my experience of maybe accidentally bumping the screen twice and activating the dimming, is that the flashlight app is still running in background, then the home screen locks and puts the app in sleep mode, and when phone is unlocked it catches up to the "1hour" setting to turn display off, and thus, dims it immediately.

I've changed the settings and will monitor the situation. If my educated guess is unfounded, i just typed a lot with my thumbs for no reason.

Good luck!

The steps posted on this site (http://www.imore.com/how-fix-auto-brightness-issues-under-ios-6) worked for me.

Same problem here.

This seems to be an iOS issue. Been experiencing tbis issue since updating to iOS6. Been happening more frequently since updating to the latest 6.1.3. Happens randomly. I seriously doubt Apple does not know about this. Probably very low on their priority list. A simple fix is to turn off auto brightness. But you lose that feature. I've turned mine off, and moved the brightness to about 45%. Not too dark, and not too bright in low light environment.

I had this problem occasionally since I had bought the iPhone 5 last September. Then sometime in the Spring of this year it never happened again and I forgot all about the dimming issue. Recently the dimming started happening again. The only thing I noticed that I can associate with the problem is that I turned Siri back on. I had shut Siri down in April/May because I kept accidentally enabling her with the home button. So I now have Siri shut down again and I haven't had any dimming problems since. Hopefully this will do the trick.

I have been holding out on the software update since it came out months ago. I finally did the update a few days ago out of desperation, since I was unable to make a direct call to my father's hospital room. The update did not correct my problem and only a few days later my screen has dimmed for the first time since I got the phone approximately 1.5 years ago.

As of today, I'm still having these issues. Only seemed to start though once I started playing the new Plants vs. Zombies. I thought it might be an overheating issue.

Well, I guess I should be glad that I am not alone in this problem, though I think the fact that this thread is as old as it is, shows how lacking Apple support can be towards its customers. I have an iPhone 4s and have had it since release, over the past 6 months, it increasingly dims own its own for random reasons it seems. I thought maybe it was just the phone and its age, however my wife just purchased an iPhone 5 and within the first 48 hours of using it the same issue has cropped up. It definitely is not our phones or their hardware and we have almost no apps that are the same so I've got to believe it has something to do with the OS itself.

For me, I guess the question is, do I purchase the 5s like I had planned, or will that OS have the same bugs that won't be fixed and if so, am I willing to put up with that in order to have the phone.

THAT is the million dollar question. I too believe it's the iOS that causes most issues with the iPhone. Usually, resetting as new, and setting up from scratch fixes problems. As inconvenient as it is. I normally don't update to the latest iOS, unless I really have to (ie. can't update or download apps requiring the latest iOS). But after reading up on iOS 7, it seems more of a major upgrade than previous iOS. To me, iOS 5.x.x wasn't that much different from iOS 6.x.x. But I couldn't use apps unless I updated. I'm hoping that Apple, in all it's "wisdom" fixes many of the glitches in the iOS 6.x.x with iOS 7. I'm just wondering if the 4S will be able to run iOS 7 with no issues. I'm not jumping on the 5S as soon as it comes out. Waiting for a couple of months or so after release.