2008 f-150 radio and interior lights randomly come on while the key is off, out of the ignition, parked in the garage, with the doors closed, the windows can be open or closed. began randomly about 2 months ago (12-1-2010 @ 60k miles). no re-occurring pattern to the incidences. if the radio on/off switch is off the radio does not come on, but the interior light will come on. local dealer replaced some sort of "radio module-$600.00" but did not resolve the issue. help; concerned about battery life and other potential electronic failures. *tr