Bluetooth settings not working, greyed out, fix

In some instances you may be unable to turn Bluetooth on or off because the Bluetooth setting is greyed out or dim, thus not working. If you experience this issue, please try the following tips to resolve it:

• Make sure that Airplane Mode is off (settings and toggle on Airplane Mode).
• Restart your device by pressing and holding the on/off button until you see the red slider and then slide the slider.
• Update your iOS version. (How to update your iOS version: iPhone, iPad, iPod Touch)
• Reset Network Settings (Settings > General > Reset > Reset Network Settings).

Related:

• Common iOS 6 / iPhone 5 problems & bugs, How to troubleshoot and fix
• How to use an Apple bluetooth keyboard with an iPad