I have a 2002 Ford Windstar 4.0 and it only blows out the defrost vents. What is wrong with my air conditioning?
You have a vacuum leak between the source vacuum (the engine) and the heater a/c control head. When vacuum is lost the default setting is defrost (that way if all fails, you will still be able to see).
The most common place to loose vacuum in under the passenger side of the dash where the vacuum line comes through. If you look under there you should see a grill that covers the recirculation inlet and there should be 2 vacuum lines attached to the a/c box. Chances are one is attached and one isn’t. If they are both attached, then you will need to get into the engine compartment and find that line. It is unhooked somewhere.