Hearing a High pitched noise

[azn toyo]

Hi all
The weather is nice so I had my windows down yesterday and noticed a faint high pitch noise coming from the outside of the car. I think it was coming from the passenger side. It wasn't limited to when I was on the brakes. The car wasn't pulling one way or the other. It was so faint that I can't hear it when my windows are rolled up.

Anyone have any ideas of what it would be?

 

[silver4est]

Does it go away when you let off the gas?

 

[azn toyo]

Does it go away when you let off the gas?

Nope. I drove it again today and it sounds like one of the brakes is grinding the slightest bit. I'll have to jack it up to narrow down which wheel it is.