If Settings shows Wifi as grayed out ("No WiFi"), then the WiFi chip on the main board is bad and you will have to replace the whole main board.

according to the teardown for iphone4 "Apple has integrated the UMTS, GSM, GPS, Wi-Fi, and Bluetooth antennas into the stainless steel inner frame." the teardown also notes that there "are pressure contacts on the inner face of the rear panel which look like they are for an antenna"

it doesn't actually identify the wifi component

go back and clean the frame and inner rear panel-check for defects, scratches etc. it may not work, but it's worth a try.

hi I reopened and found out the couple of screws were not in he right place as their are many screws of different sizes I just rearranged the screws according to the ifixit guide and it worked out perfectly.Thanks for your reply.

if you have no wifi the gold antenna at the top is most likely damaged

Good News Everyone! After I had spilled water on my device about a year before and I got the same problem: my wifi was greyed and bluetooth was not working either on my iPhone 4. I tried all possible solutions:

1. Airplane on, turn the iphone off, turn the iphone on, turn airplane off, and then wifi was supposed to start working. BUT not with my device(

2. Freezed it for 30 min in a plastic bag. BUT it was a time waste.

3. Then settings-general-reset network settings/all settings. BUT it didn't work.

4. Eventually I diassembled my iPhone 4, removed all 5 screws from wi-fi antenna (NB: pay special attention to 4.8 mm screw, as it is supposed to be the primary reason for wifi bad performance), cleaned all these screws and all metal-to-metal contact points on the connector cover with a de-greaser. Then reassembled it

AND WI-FI APPEARED!!!

Thanks to ifixit)

I dropped my iphone 4 in water. It didnt even completely sumbmerge in it but not my wifi is grayed out and wont work. What do I do?

Where is this screw your talking about? I know I have some missing

on wifi antena on iphone 4 where does each screw go because i have 5 and they are diffrent sizes and im not sure wich one goes where please help asap thanks

Not long off the phone to apple as my wifi was greyed out

And what they told me to do was add other user account on my laptop and try

Reinstalling latest update via iTunes and presto wifi back hope this helps others out there