so, ive been dealing with this for a few years now. whenever i have either the heat or the A/C on, as soon as i give it gas or go up a hill the air coming through the regular vents, immediately redirects through the windsheild defrost vents... i then have to let off the gas for a few secs for it to come back through the regular vents.

has anyone else run into this problem and figured it out? i checked all the vacuum lines in the engine bay i could find and none or loose or have cracks?

and i DO NOT want to take it to the dealer for the fix.

 

From what i found theres a vacuum resivor behind the glove box. Make sure that its not cracked and the lines to it are good. Also if thats good theres a a/c check valve inline somewhere with the line that feeds the resivor. That also could be bad. I believe its under the hood but i may be wrong. it should have three vacuum lines going to it. I tried to find a pic but no luck. Try following the black vacuum line from the vacuum resivor to it. Hope this points you in the right direction. Also there can be a few other things bad. vacuum lines ofcourse.,also the vacuum motor that controls the door operation can be leaking, and the control head itself could be bad.

 

thanks for the direction. is it difficult to check the res behind the glove box? will i be taking things apart to get to it? just trying to plan a repair time needed.

 

from the discription it said to remove the glove box and it should be mounted right there.

 

Yea check the thing under the dash... its like a metal saucer with a vac line to it...

You dont have to unbolt the glovebox, just take everything out, then squeeze the 2 sides in and the little stops will fold in and lower all the way down.

I had a navigator with this issue, and the vacuum line off the controller was dislodged... So you have a vac line off/broken somewhere..

 

hey guys, I've been having the same problem with my 200, Ford confirmed that it is the vacuum motor, now how to replace it? I need some help and pointers, supposedly the dash has to come off but I would like more help please. I dont have $578 to pay ford to install it

 

let me know what you do to fix it and how much the part(s) cost... because i still havnt resolved mine. i checked all the lines and everything was fine.

 

the part is $20, need someone who has the manual for new edge mustangs for the air conditioner, since it has to do with that. Vacuum control motor is mentioned in there as well as how to get to it by what we need to remove to fix it......been searching the forums, let me know if you find anything I will too.

 

I think your problem is not the lines them se,ves but a bad check valve, since this only happens under a load which is when the vacuum drops off, probly not a bad line, if it were it would fail all the time

 

For mine, ford replaced the check valves and it was still doing it so they said it was the motor