If your heater blower does noises like Sopwith Camel in flight or just doesn't blow strongly enough then this how-to might be for you. It's an easy 30 minute job which requires only basic tools, the hardest part is to yoga yourself under the glove compartment to get access to the motor itself.
you only need:
phillips-head screwdriver
flat-head screwdriver
light source
Here's how you do it:
They say always disconnect the negative battery cable when dealing with electric stuff so that's what I did first.
Alright, the blower assembly is located behind the glove compartment.

To get some more room move the passeger seat back as much as possible.
Now you need to get yourself down there somehow, undo these three screws and remove this plastic cover.

Next you'll need to undo these two screws, that's essential to get some wiggle-room later when removing the blower motor itself.

Then take off this black plastic cover. There aren't any screws, it just slides down.

Next you'll need to disconnect this connector and the tube. The tube needed some light prying, that's where I used the flat-head srewdriver.

Now you can unscrew these three screws holding it in place. (The third one is not visible in the picture but it's not that hard to get to)

Finally, you can get the blower motor out of there, you have to slightly turn it and then wiggle it out while pulling the metal bracket out of the way, that's why the two screws had to be undone in the second step .
Now you can take all the junk (and money??) out of the blower fan and clean it.

or you can just replace it if it's beyond saving. For me, just getting the junk out of the blower fan made all the difference, the fan is so much more quiet now. There's nothing tricky about installing the motor back, it's the same process as removing it but in reverse. Overall it's an easy, quick and satisfying job and you can even make some money out of it.