Air flow issues

[t33r0y]

We recently purchased a 2007 Ford Explorer. The air has been acting up recently and wanted to get your opinion. The air will flow out of the front vents fine but will all the sudden change to blow out of the defrost vents and then a few minutes later switch to blowing out the front vents. I am assuming this is a vacuum issue or something that is controlling the vacuum but I cannot find a vacuum diagram yet for this vehicle. I have not done anything yet to investigate this issue other than try and look some things up online about it. I have yet to find someone who has had this issue and was hoping someone here may have seen it.

Any suggestions you have would be greatly appreciated.

 

[Rcflyer330]

It sounds like its your ac check valve in the engine bay. Do you hear a hiss when you accelerate that sounds like its comming from near the passenger footwell?

 

[06Exp]

Nope. No Hiss.

 

[t33r0y]

Unfortunately I have not gotten to check. This is not an everyday driver and have not had the time to check. Once I do i will update the thread but thanks for your input.

 

[MotorCityFats13]

mine does this from time to time while pretty much only getting onto the express way but not every time... only exception is i can hear the fan motor slow down... every time its done this the resistor magically dies about 2 months later

 

[t33r0y]

It does appear that the check valve may be the issue. I can hear air escaping when accelerating but I am not sure where the check valve is. I can see the vacuum reservoir under the dash and assume it is near there but does anyone have an image of what it looks like or a diagram?

 

[Rcflyer330]

Its by the firewall passenger side in the engine bay near the top. The actual coler is half black and half white (its more yellowish white).