Samsung Galaxy S4: Flashing Blue Light:
Hello. By default it means that you got a text message or some kind of notification. If you are on the home page after opening the lock screen and your text messaging app doesn't show that it received a text message (if it shows it received a message there would be a one next to it, near "Messaging" app)

Then, with one finger.. touch the screen at the top of the phone and move finger down the screen (while still touching the screen).. you should see the notification area.. under the settings of that area it will show what is alerting you:
notification screen:

If you still want to turn this off.. go to:
Settings>Device>Display>uncheck LED indicator:
tipLEDindicator.mp4
.
×