On a recent 700 mile family trip, our '07 Navi L developed a strange sound from the dash. Initially it sounded like a blown-out speaker crackling, but it only does it at high speeds and it will still do it when the radio is off.
I believe I've got wind coming through the firewall or an air intake somewhere, and it's hitting something thin that just flutters in the wind... giving me this terrible crackling sound.
Any guesses where to start?
We're driving 350 miles tomorrow and another 350 in about a week, so I'd like to get it quiet!
Sorry for the vague description. I found it difficult to disassemble the dashboard while driving 70 miles per hour and I didn't think my wife would want to do it, so my information was pretty limited..
Subsequently, I found a peice of windshield trim that may have been my culprit. Its the black peice the runs from the top to bottom on the passenger's side, partly inside the weatherstripping adjacent to the door.
My hunch is that when this trim went from "tight" to "just a little loose" the high-speed airflow created my noise. When it went to "nearly falling off" the air could easily rush by it without making any noise.