How to scan for available networks on my Apple iPhone 5S
You can scan for available mobile networks if your Apple iPhone 5S isn't connecting automatically, or if you want to switch networks while roaming.
1. Touch Settings.
2. Touch Carrier.
3. Touch the slider to turn automatic network selection off.
4. Wait while the iPhone searches for networks.
5. The available networks will be listed.
Select the network you want to use.