I fixed my blend door for free. I had been doing some research on the issue and decided to fix it with a wire hanger. Dropped the three screws out of the fan, reached up and wedged the door back against the firewall side, then folded an entire hanger in three sections and shoved it into the hole. The only warning I have on this is to ensure then hanger is wedged to the left some so it does not fall out. I tried to get the hanger out and could not budge it. I am 99% sure it will not move. Here's a short video I did on it. The only change to the video is to note that I removed the cut hanger and used a full hanger.
As a result, I now have full air flow and no more rattle. I am satisfied, even if the air is stuck on recycle. That's not a problem for me.