I only have green led and I cannot locate where I can change this option. I saw a coworker with exact same curve from tmobile and hers has red, blue, etc. The only diff bet mine and hers is that I got mine 1 month ago and she got hers 1 week ago
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JiveTalk will let you change it for IMs. Otherwise, blue is for a BT connection, green is to say you've got signal, red means you've got SMS, MMS, or email.
I haven't used Bluetooth in a long time, but I could have sworn that my indicator was a constant flashing blue when I had it turned on. Are you sure you have your Bluetooth properly set up and turned on?