Okay, I got the old blend door actuator out and took it apart (the rear mounting screw was a major PITA, as usual, and after it came out I dropped it behind the heater box (not the first time this has happened either)). Loosing the rear screw doesn't bother me, because there is no way in hell I'm ever putting it back in there.
I took the actuator apart and found what I expected to find. Small nylon transmission gear was missing several teeth. I checked my other broken actuators and they all died the same way, so no salvage repair possible.
I removed the large plastic crescent-shaped gear from my old actuator, removed the metal "feather spring", drilled a small hole in the front corner of the gear and made a pull handle from a piece of bailing wire. Pulling the gear toward the interior opens the blend door and pushing it away closes it. Open you get heat and closed you don't. The pull wire needs to be wrapped around something to hold the blend door in place, or the blower fan will move the door around. So, for now I have heat and I'm happy (more arctic air is expected for next week).
The Motorcraft actuator I liked (pictured in post #5 of this thread) does not have the same part number as mine (mine shows F87H-19E616-AB ATC and the picture in post #5 F87H-10E694-AB ATC) and the mounting holes are not the same. This actuator does say it will work in a 2001 Explorer w/automatic HVAC controls and while the exterior case of the actuator is a little different, it looks like it has pins that would go into where the screw holes are in my old actuator. I don't know if I can make this work and I don't want to take the chance ordering this part. I've searched the internet for my exact part number and I've found nothing, so I may be stuck having to buy the Dorman part. For now, both my EATC equipped vehicles are working with my baling wire fix. I just open the blend door for the winter months and close it for the summer. I'm even considering buying a universal push/pull choke cable to mount in/under the dash so I can control the crescent gear manually. Actually that sounds like a pretty good idea to me and would only cost me $10-$14 (see pics below). I'm not a fan of automatic controls anyway. Redneck fix? Yes.
Basic cable for $10:
or this one with lots of hardware to make installation easier for $14:
