I have a 09 Ranger fx4 and the blower for the heat and the ac wont change or rather change all the way.
it will sometimes only blow out the floor vents and sometimes only the windshield.
But I cant get it to just blow out the dash vents.
it is blowing and it will sometimes switch between the two.
any ideas what it could be and how I would fix it?

 

In the engine bay, passenger side at the firewall you will see TWO hard plastic vacuum lines, they look like wires
The Grey one runs to the heater hoses valve

The Black one is the one you want to check
The vent doors in the cab are vacuum doors, they are opened and closed by engine vacuum power
Engine vacuum changes from high at idle or cruising to low or 0 when accelerating
So car makes use a Vacuum Reservoir, like for power brakes, to hold stable vacuum for the cab vents

The black plastic vacuum lines runs to the Vacuum Reservoir, usually located passenger side front of vehicle down very low in the engine bay, looks like a black plastic ball
The vacuum line from firewall can be damaged by exhaust heat or just age and it cracks, so follow it and check it closely, it can be repaired using rubber hose, plastic is just cheaper which is why car makers switch to plastic lines

Vacuum reservoir could also have a crank so can't hold stable vacuum, just have to pull it out to check

Its possible a vacuum hose in the cab has been pull off or is leaking but really a big long shot unless you have had work done recently under/in the dash

 

I believe I found what you are talking about but it connects into a grey elbow and before I go and pull on it and possibly mess something up is the a way I can get you to send me a picture?
it looks like the tube runs to the cover on the engine that states 4.0 from the elbow

 

Look at this picture of the heater bypass valve: https://www.ebay.com/itm/Motorcraft-...-/371176315424

The cylinder on this valve has a Port for the Grey Vacuum line, thats NOT the vacuum line you want to check, but follow that line over to passenger side firewall and next to it at the firewall will be the BLACK plastic vacuum line..............this is the one you want to follow to the Vacuum Reservoir at the front of the engine bay, checking it for breaks

This drawing is best I could find: https://www.ranger-forums.com/attach...-line-6abx.jpg

Grey hose is the one circled with ?

Arrow points at vacuum reservoir

Black hose runs from reservoir to firewall, dash lines

#4 is also a black line but runs to engine not firewall

 

this is one of those times that makes me miss my f150. I could fit n the engine bay vs with the ranger it is so freaking tight I think I found what you are talking about I even found it connected to a T if its the right par I will snap some pics when I get home today and maybe upload them before I tear anything up

 

Haven't looked at a 2009 specifically but shouldn't be a "T" on the Black line between firewall and Reservoir Ball
Its possible Ford added a "T" for the EGR system in later years

If you can find the Reservoir ball there should be 2 black lines connected, the one to the firewall and the other one runs up to the upper engine/intake manifold, it can have a "T" on it
This second line is how you can test reservoir ball using a vacuum pump or your mouth, lol, just suck on that hose and it should hold vacuum pressure if not then there is a leak

There will be a vacuum hose diagram on the rad support