RobinsonM,
One of the posts repeatedly gave this great hint metioned it towards the end. I think that this should be stress from the start:
place you Electronic control unit ALL THE WAY TO THE COLDEST, the natural closing position of the blend door. So that when you are reinstalling the dor it is easier, not easy but easier.
The headlight switch: I had to remove it. You need to turn it all the way to on/fog lamp on and then remove it by prying with a small flathead screw driver. Then re-insert it at 180 degrees from this position, in other words, you need to pry it off at on position and re-insert it "180 degrees wrong" and then turn it back as if to shut lights off. By doing this it will disable the plastic latch that holds it in. You need to take it off so that you can take the cable harness off and a screw (you may not need to remove the screw, but I took it off anyway).
As far as the middle of the dash, the radio and temp controls are held by a frame that I removed and also a couple of screws that are behind the radio. Tha allowed me to move the dash from the middle.
You also need to remove some of the screws that hold the steering column and then the dash will come off towards the "back" and allow you to get to the plenum, This is all assuming that at this point you have most of the other screws off and are havinf trouble in the middle only.
Although I just pulled the dash as far as I could WITHOUTH removing the steering column and managed to get to the plenum and remove the 13-15 screws (8mm) that hold it together (most are visible, but look out for the three that are in the back and sort of hidden). I had my brother gently pull the dash towards the back while I removed the plenum cover and removed the door and replaced it. It is definitely a PITA... but having said that, get yourself a buddy and take the time to do this. You will definitely HAVE A BIG SMILE, once you're done and think of the $1000-$1400 you save, depending on which dealer you call. I am extremely busy with work and just tackled this PITA a hour per day at a time and eventually, with GREAT PATIENCE, finished and am enjoying the awsome Hot air now.
If you have any other specific questions send me an email. Because now after the fact, and of course after all the headaches, I have acquired the FORD/LINCOLN NAVIGATOR/EXPEDITION manuals vol I & II and the electrical and vacuum books as well.
Thanks to everybodies previous posts, pictures, hints, and suggestions. I can now say,
................... I did it !!!!!!!!!!!!...........