Hi guys I have a problem with my 2000 town car and I hope someone can shed some light on it. The miles per gallaon reading does not indicate. There are just three lines showing like this _ _ _ when I acti8vate it. The same thing happens on the distance until emty indicater. Yet all the other things work on the readout. Like trip miles and such. The local dealer changed the head unit in the dash (or so he says) and that didn't help. I think that they don't know what to do next. HELP HELP