Max AC switching from Vents to Defrost (check valve questions)

[CoachKelly]

Hey guys, I have the typical problem when the AC is in MAX mode (doesn't happen in 'normal' AC mode) under acceleration/load, it will switch to the defrost. Letting off the gas or switching to 'normal' mode pushes the air out the vents again.
I've searched high and low and can't find this mythical check valve to test it. Can someone post a pic or a diagram of where to find it please?

Thanks in advance.

 

[swshawaii]

This?
https://www.rockauto.com/en/parts/motorcraft,YG360,vacuum+control+valve+(vcv),4980
I don't believe 2001-05 (Gen 1) has the YG-360 vacuum control valve.

 

[CoachKelly]

I would assume that's what it looks like. If the 2001s don't have the vacuum reservoir or the check valve, that MIGHT explain why I can't find mine. LOL

 

[Todd Z]

The vacuum ball is INSIDE the front passenger fender.... 2 plastic lines go to it.... Maybe the motor replacement hacks removed all that stuff, but that's where the ball is.