Success! I replaced the recirc door actuator today. What a pain in the ass. Almost gave up a couple of times, afraid I'd never get things back together if I kept prying on things to make room. Had to remove the dash cover (not hard, followed instructions from the tech how-to master list) but then I could only see a tiny part of the actuator. Pulled all the fasteners from the ductwork but it would barely move so I forced it back to clear the outlet holes, and up, then got a 2' tire iron and pried up using the metal back by the windshield to pry against and about 5-6" of wood blocks resting on the front metal framework of the dash to hold the front of the bar up. This gave me just enough room to get a hand through there and remove the one screw I could see. Sparky's video listed it as 5.5 mm but a 6 mm 1/4" drive socket worked. The back screw was a real challenge; it's impossible to see. I used a short screwdriver handle with a socket adapter and got it out blind. Barely. A tiny bit of a turn at a time. (It didn't get reinstalled). Then I had to hook a piece of wire onto the door and move it back and forth with my right hand while I tried installing the actuator with my left hand until it finally slipped into place. Wow. There is one locator pin and one screw in the new one and it felt solid. There was no way the back screw was going back in without completely removing the ductwork which would take hours. Started the truck, left the controls alone for 5 minutes in case it needed to relearn anything, then hit the recirc button and...it works! Nice and quiet and I can see the door opening and closing. I could see from the position that the old one was in when I removed it that it was in recirc mode all the time before even though it was set for fresh air. That must have been why it would occasionally start squealing- it would try to move the door to the correct position and eventually give up. Total cost was $53 from RockAuto and 2 hours of my time. I've heard of $500 and up quotes from shops to replace this part. The service manual states to remove the ductwork completely. I think in order to do that the entire dash frame and sub frames have to come out.
