Sound under the dash

[miki_373]

Hi guys. Im not sure if this question belong in this section, so if it does not I'm sorry. Anyways, I got a weird problem. After an 800 mile trip I started noticing weird noise coming from under the dash somewhere. It sounds like electrical buzzing/static. I can change the pitch of the sound by overloading the electrical system (trying to close already closed window). It only seems to happen with engine warmed up and idling. I was thinking its some kind of a motor trying to do something or maybe vacuum pump, but cant be sure. Anyone have any ideas? Thank you.