I have a question that several people have already asked on other sites but did not get an answer for. Or if they did, it was vague and unhelpful. Hopefully I can provide a bit more of an explanation.

My 2001 Ford Escape XLS makes a constant, dull humming noise that you can hear when at a stop or driving around town. It doesn't do it at highway speeds (60+ Miles Per Hour), nor when I am applying light pressure on the brakes. And sometimes it even stops when I am turning left, but never while turning right. Also, it does seem to change when adjusting interior A/C levels. The sound is coming from the passenger side, closer to the front, I believe. If you have ever taken a glass bottle with some liquid in it and blown across the top, you know exactly what this sounds like, because it sounds like that.

So if you know what it is, that would be great. I have read people saying it was the wheel bearings, a belt, something in the engine, or the "Electric Fuel Pump" and other random things. If anyone has any confirmation on either of these or something else, that would be fantastic, thanks.
Also, keep in mind, I have very little knowledge of mechanical lingo and stuff like that. So please speak in words I can understand. No abbreviations please.

 

Also, I am not 100% sure on this, but I will be able to confirm it later today: It seems to me that it doesn't make this noise when it has a full tank of gas. I seem to remember it only started when I was at about 3/4 full. I will try to get back later today to confirm this.