Very easy to remove. Refer to the attached drawing, you need to go in through the glovebox opening and remove the nut (#7 in the drawing).
Jerry
The speaker is where the glovebox opening is, but you don't have to get to the nut from the "top".
You can reach up under (a flashlight helps) to loosen the nut, I seem to remember a 7/16 wrench fits.
When the nut and bolt and plastic spacers come out, there is a "guide slot" on the top of the vent door that limits how far the door can open and close.
Sometimes it can be slid off of the "guide pin", sometimes(in my case) it can't.
I ended up using a sidecutter to "snip" the middle of guide slot the top of the vent door, so it would slide off of the guide pin.
Hope this helps...