What part of the heater/blower would make a "hum"?

[pagluy]

New car has a couple smallish issues. 1st and foremost is when the heater is blowing, I hear a hum that changes with the speed I have the heat set on. It's pretty annoying on anything other than the lowest 2 speeds, and when I turn off the system it goes away completely. Any ideas?

 

[jcharb]

could have some leaves or something else that has made it's way down there, which would either be like putting a baseball card in your bike spokes, or throwing the blower off ballance, either way may need to be taken out and cleaned up

 

[Eric0508]

my dad had this problem in his pilot. Ended up being a mouse that was stuck creating a similar problem as described by jcharb