Hi,

My Chevy Blazer 1998 LS 4 doors 2WD has some unpleasant noise audible inside the cabin. It is there while idle or while driving but not pressing the acceleration pedal. If I press the pedal it disappears for a while.
It is like a whining hum accompanied with some crackling.

I carefully recorded this issue on videos, please take a look.

Could you help me find out what it is and how to get rid of it?
Many thanks in advance!

upd: I found out that when I press on the electrical button that rises\lowers the windows while the window is closed (like I`m trying to close it more) I can hear that whining hum slightly changes its pitch while the voltage drops.

<iframe width="560" height="315" src="https://www.youtube.com/embed/G9dGJ3W5Mtc" frameborder="0" allowfullscreen></iframe>

<iframe width="560" height="315" src="https://www.youtube.com/embed/5s_xhUnfN2U" frameborder="0" allowfullscreen></iframe>

 

some local mechanic told me it could be alternator which somehow transmits its noise to the inside of the cabin. any ideas?

 

Heard a whirring sound, sounds like airflow... ?