Q: iOS, iOS7 auto-brightness fails

I agree....Auto Brightness doesn't work for me since ios 7!!

Auto-brightness works for me in iOS 7.

Read this: http://support.apple.com/kb/HT5506

Also note that auto brightness does not dim the screen immediately when the ambient light sensor detects dimming light, if it did the screen would dim every time your hand covered the sensor. If you move to low light the dimming feature will work when you turn off/on the screen.

Could that be why??

So my ipad isn't having any hardware issues??

My auto dimming worked on my iPhone 5 after updating to iOS7 for a while and then quit. I resolved the issue by resetting my settings (Settings > General > Reset > Reset All Settings). After doing this, the auto dimming feature worked.

Be advised, all settings get reset such as location services, accessibility, Home and Lock screen pictures, etc. After resetting, all these settings must be set back to your personal desires.