2004 Ranger, XLT, 4x2, 4.0L SOHC, AT, 230k+ miles
I am having a bit of a problem with the A/C duct control. At idle or high vacuum operation, it works fine. During cruising speed or under acceleration, it switches from dash vents to defroster vents by itself. Manipulating the control ****/switch does not return it to the selected position unless the engine is again operating at a high vacuum condition. I tried replacing the vent door actuator but no change.
I am sure you guys know more about the operation of this system than I do, so I beg for your help.

Thanks you guys!

 

some where you have a vacuum leak in the system. when the system loses vacuum it defaults to defrost.


you should see a vacuum harness running along the passenger side of the engine *i think*. Ill take a look at mine today and see if i can get some pictures for you

 

Thank you. That would be helpful.