On the passenger side basically behind the glovebox I can sometimes hear a very quiet whining noise it doesn’t happen often and is very hard to hear usually. Then closer to the driver side behind the dash I sometimes hear what I can best describe as the sound of like a cd drive ejecting a disc or something like that though it has nothing to do with the actual cd drive in my car.
Model and year ?
Adjust the radio volume up enough so you can’t hear the noises.
Does this happen only when you change HVAC setting? That could be an actuator going bad.
On passenger side could be debris in the HVAC fan or bearings.
This may be the 2007 KIA Rio that he has several threads about.
I think you and others must be detailing so much stuff from posters. Must be a hell of a spreadsheet, other poster was like you are in WI, well yes I am. I cannot remember what I had for breakfast, kudos!