Is the 12v hole in the wall plate for the TV booster? If so then most of us will have it. We have been plugging our phones into the 12v on the dash at night. So I guess that is why we have not had the problem. I have the 12v charger because I like to listen to Pandora on the cell phone through the dash radio. When I do it tends to run the battery down. So I plug the phone into the dash and the ear plug into the aux/line in hole on the dash. I am not sure if Phoenix still installs the aux/line in on the dash. I had to ask for it on the second PC.
1) The 12v is in a wall plate with what looks like a coaxial cable screwed/plugged onto the top half. If that cable is the TV booster, then yes, it's on the same plate (someday I'll figure out what a TV booster is).
I have made this mistake more than once. Check your TV setting for signal source cable/antenna.Barry