2006 model...I am having a defrost only issue, I know its the actuator but I dont know where its located EXACTLY. I pulled the glove box down and looked behind it. I see a electrical actuator but that looks like a blend door one, not one the changes vent to defrost. I have good vacuum at the little ball undre the hood. and traced the hoses into the cab. So not sure if there is a wasp nest in the vents vkeeping things from moving as they should. Thats why I want to know exactly where its located so I can stick my hand in and hope for best..

 

Ok, I found all 4 of them. On is right behind the glove box to the right. 2 are over on the driver side up from the gas petal. and 1 is under hood to divert hot coolant. I manually activated all of them. Very easy for 2 of them, other 2 where stiff but worked all way thru motion that they normally do. So no wasp nest behind them.
Trouble shot the vacuum as thats what makes them move. Had good vacuum at the little ball under the hood in front of pass tire. So too the feed hose from inside and tried to pull a vacuum and got nothing. Pulled the supply line on the inside and tried to pull vacuum and still nothing. So I knew it was in between the fire wall . I pulled the liner out of the wheel well and pulled the 1 supply line, its black, gray goes to coolant diverter. I tried blowing thru the hose and could not do it. Found either the heat from exhaust had closed it up or ???? but dont see how it could have been closed or crushed. Where it sets is impossible to crush and heat does not see to get under there. So it could have been this way from factory and the people I bought this truck from just dealt with it.
FIX was a new 3 foot piece of hard plastic hose. I could have spliced it back together, but doing it once and forget about it...

 

How did you manually activate?