Squealing A/C - Heater Fan?

[ntsaint]

For the last few days, when my AC or heat is running (it's 40 in the AM and 80 by mid afternoon here, welcome to Louisiana) I've started to get a very loud, very annoying squeal coming from below the glove box. I got down there this morning, and it's definitely coming from the assembly in the below picture. When i tap that black case, the squealing stops (it's like there is a fan or motor off balance, or about to fail).

Before i start digging into this, thought I would see if anyone else had run across this, and if so, what the fix was?

Picture was taken looking UP from the passenger floorboard.

 

[Coolstream]

Usually it's the brushes in the blower motor, but you might pull it out and see if there's anything like a piece of paper stuck in the squirrel cage. Once you have it out, spin the cage and you can often feel roughness in the rotation.

 

[RobRed]

3 screws, 1 power connector, 30 seconds to remove.