Hello, I am John, a Ford dealer technician.
I hope I can help solve your problem quickly and accurately.
It sounds like you have a bad temperature blend door actuator. This is what moves the hot/cold door in your dash. It has plastic gears and when these gears strip out this is the noise that it makes. To replace this you need to remove the center console assembly then you can get to it. I am posting instructions on how to remove the console and the blend door actuator.
Click here for console directions
Click here for blend door instructions
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