Wifi won't turn on its greyed out
I have a 16 gb iPhone 4S and the wifi can't be turned on its up to date and its starting to get frustrating I need help AT&T says its apples fault
iPhone 4S, iOS 6.1
Try the suggestions here to see if they resolve your problem:
http://support.apple.com/kb/ts1559
If these don't work you may have a hardware problem. Visit an Apple store for an evaluation or contact Apple Support.