re: "There is a corrugated door that regulates the fresh air/recirculate and that is what she heard. It also moves after a door has been open or closed."
I don't hear stuff when sitting...but on entry as I open door, there is ALMOST always a rather ominous but brief heavy buzz like 'something' was going on and terminated when I was discovered ......most often first thing in AM but sometimes during the day when running errands....sometimes doesn't do it at all.
Doesn't sound like a CD player to me.
The other odd happening, is the seemingly random switching on of the overhead light...sometimes on when entering, and sometimes not.
That in itself isn't the issue....but the fact the actual light-stalk is rotated to "on" when I know it wasn't left that way.....and requires I physically turn it "off".
I've grown used to the behind-dash gurgling sound on start up of engine....also randomly present ....or not....
get in--buckle up--hang on
"soothing agricultural implement/personal servant/Walter Mitty multidimensional access utility device conveniently travels on pavement when necessary and often keeps me warm/cool/dry/soothed as needed."