wifi can not be turned on

It has been found that some iPhone 4S' had a different, faulty WiFi chip that would tend to overheat and break after certain upgrades. Apple allowed owners to trade in their broken iPhone for a while, but has since discontinued that program. I know it sucks (this happened to me), but there are some..... "sketchy" ways to fix it (temporarily).

1. Freeze it.

Place in a freezer for about 15 minutes, then turn it on. The WiFi should work..at least until the chip heats back up.

2. Overheat it!

This is very risky as it involves heating the phone up in an attempt to reflow the solder holding the chip down. There are multiple guides on the web describing how to do this.

Both these methods are extremely risky and are not recommended. From personal experience, the freezing method worked long enough for me to do an iCloud Backup and get a new phone. The WiFi chip is extremely hard to solder back into place, and probably will only overheat and push itself out again.