Weird noise when turning on car and turning off air

[Schemern]

Hello all,

I am new to this forum and just bought my 1st SUV. It is a 2004 Mountaineer and I have a few things to do to get her running strong. The first thing is a transmission pan drop and filter replacement (excellent walkthrough on here), the next is figuring out why I have shaking when I go above 60 mph (hopefully just unbalanced wheels), figure out why the rear wiper and fluid won't work; but the last issue I am not sure what it is or where to start. Every time when I start the truck or turn the air off, there is a loud noise that sounds like it comes from behind the center vents/dash. The best way I can describe the sound is like a speaker with static or not being grounded (that annoying interference/scratching sound). I made a video of the noise. I couldn't hear the noise when I started it, but it does seem like the video picked it up. Let me know what you guys think and I hope to be able to contribute to the forum in the future.

Here is the link...https://youtu.be/SbEY8VWGidY

 

[Joe in NY]

sounds like your fresh air damper scraping as it swings. when you turn off the DATC it either opens or closes the fresh air damper using vacuum. I can't remember atm. I have the whole diagram for what gets vacuum for every setting on the DATC

 

[TechGuru]

I believe "Off" and "Max" it's closed (recycle mode) and all other settings it's open. It is recommended to leave it on any setting other than "Off" or "Max" to allow your vehicle to "breath" though it when parked.

 

[Schemern]

Thanks for the responses. I will look into this further this weekend and let you guys know what/if I find anything out.

 

[Joe in NY]

when you shut the car off it does not matter. Ford uses vacuum to operate the recycle door and air flow doors. When the car is shut off you lose the vacuum and the doors reset to default

 

[TechGuru]

when you shut the car off it does not matter. Ford uses vacuum to operate the recycle door and air flow doors. When the car is shut off you lose the vacuum and the doors reset to default

Um, the vacuum should hold unless you have leaks as there should be a check valve. At least this is how my MBenz is. It even has a vacuum reserve sphere. Many vehicles you can change the a/c settings after turning it off and hear the flaps move though a few setting changes until the vacuum runs out.