GreenZinnia needs blend door actuator advice

[GreenZinnia]

Hello all!
2010 Ford Expedition EL
Loud knocking sound from dash - doesn't matter if a/c or heat are on or not
Does it constantly some days, others not at all
Front and rear blowers both refuse to work consistently - Kicking passenger floor vent area of console sometimes brings front blower back

So question is: WHICH ACTUATOR IS THE PROBLEM? Glove box or behind center console???? Actuator replacement sitting on my desk as we speak.

 

[mdall1979]

Do you have the navigation system. If so, its easy to take out and gain access to the center motor and you'll be able to see and feel if it is the one clicking.