I have the same issue, I had hoped that the upgrade to IOS7 would fix it.. Nope, nothing, my battery doesn't even last anymore..
I have tried the freezer trick, but never dared to leave it inside, more than 15 minutes.. It does fix it temporarly, when I say temporarly I mean, if I try to restaure the phone, or restart it, or even nothing.. wifi becomes greyed out again.
If I do nothing, it's not greyed out but finds the wifi, right away and then loses it, and finds NOTHING.
This is a joke. Period!
If your wifi is greyed out do the following:
1) Put your phone on a plastic bag and then in the fridge (not the freezer!).
Wait around 20 minutes to take it out.
2) The moment you take it out reset your network settings.
When the phone turns on, your wifi wont be greyed out.
The problem you might have is that it wont pick up any networks at all. Which is my case.
Honestly, apple should be ashamed, i bought about 7 iphones, 6 ipads and 6 mac books over a short period of time, i am using the iphone 4s and as many people mentioned the wifi is greyed out, i went to the apple store and they said its a hard ware issue and i need to pay 200 usd (in china shenzhen)
I mean my phone is 1,5 years old and it seems like millions of users have these issues
Apple you guys should be ashamed!!! I will switch away to samsung
In the long run you guys will loose apple, jobs would have never allowed this
So it's very simple. All you have to do is go to Settings>Controle Center. Turn off the access on lock screen, then turn off your device. Then turn on your device back. Go back to setting and wifi, normally it's will work.
Sorry for my bad English, because I'm French.
my daughters Iphone 4s WiFi card went out three weeks short of the warranty going out. Went to Apple store and they replaced her phone but said since we didnt buy extended warranty, the new phone was a replacement and so its has only two weeks left. We have 3 other Iphone 4s in household with no problems. But guess what? Three days after getting new phone this WiFi card went out also. Made appmt to go back tomorrow as last day of warranty. Not sure if I should be real upset and or feeling lucky. I am anxious if the next phone will work correctly.