And the verdict is.......?
Well, so far I have found out what is not causing the issue:
1. Speed limit warnings from the Navigation; I get no indicators on the unit when the bells ring.
2. Phone plugged in or Bluetooth; I don't keep the phone plugged in and I get the sound when the phone is off.
3. XM music and following an artist or song; sound comes on with radio off.
4. Unread texts; I usually read my texts right as I receive them and pretty sure that is not the cause.
5. Using Waze; nope, don't use Waze.
6. Active Noise Cancellation (ANC) issues; don't think so as ANC comes from the rear speakers and the bell sounds come from the front.
7. Dealer installed insurance/inventory GPS tracker; I did not find anything attached to the ORB port (besides my AMP power steps) and bell sounds are a recent phenomena occurring way past the time since I purchased the truck and/or added the steps.
8. Hari Krishnas hanging out under the truck; none found...lol.
9. Merge warning from blind spot indicator; nope, as the the bell sounds come on when driving with no other vehicles or objects around.
I am amazed at all of the creative ideas and really appreciate everyone's input! This is turning into quite the puzzle for me to figure out.