I'm a new s5 owner and when connected to wifi the 4 or 3g is still on. I had this issue when having the s4 and was cuz of the caller ID ap. ..which i turned off off and solved with turning off the ap....any suggestions
This is a normal behavior now! If it is greyed out, then it is off. They are rolling out the new VoLTS service and will keep the data connection on now...all the time
After the 4.4.4 update, the Verizon S5 is capable of VoLTE (Voice over LTE). The LTE connection has to be maintained in order for VoLTE to work. But it's only on for calls over LTE, not for the transmission of any other data. Notice that the up and down arrows under the 4G icon aren't active? That's because no data is being transmitted over the network. Your WiFi is still doing all of that. And this will be the case regardless of whether you've enable VoLTE or not.