How to get Auto-brightness to work on iphone 4?

I've read so many websites and all of them claim to have a fix but this fix isn't working for me.

I have never been able to get it to work, even before the Auto-brightness overhaul in IOS6, it doesn't matter whether the slider is set to on or off the brightness level remains the same.

I've tried calibrating my device

- Go into a dark room
- Turn auto brightness off
- Drag the slider all the way to the dimmest setting (or which ever brightness you're comfortable with)
-Turn Auto-brightness on
- Step into a light area and it should auto adjust

But this doesn't work, I try this and it just stays at the dimmest setting after going into broad sunlight.

So I tried calibrating it for bright too, turned auto off, dragged the slider to 50% / 75% and turned it on, walked into a dark room and it's still bright.

Any suggestions?

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