Q&A

 Master

These don't have a heater valve, the coolant is always flowing through the heater core (normally). Sounds like you have a plugged heater core. Try flushing it out, and if it is plugged flush the entire cooling system.

 Rookie

I did not author this, i would give credit to the author, but i cant find his name. I confirmed the information tho. I hope this helps.
Answer
There are a few things that could cause this to happen. On many vehicles there is a heater bypass valve on the water line that feeds the heater core. This is located under the hood and operated by a vacuum line. If this part is bad, no anti-freeze will run through the heater core. Another possibility is under the dash. There is a panel which opens and closes the hot air duct, located near the heater core. This is operated by a vacuum diaphram, which could be bad. It sounds to me like one of your selectors have gone bad. All of the vent controls run on vacuum, and the switch that selects them, or the temperature, may not be transferring the vacuum correctly. You can check the hot air duct diaphram after the engine is warm. First, watch the rod and switch from cold to hot to see if it's working, if not try the following. Have the selector on cold, and the vacuum line disconnected. Put your finger over then end of the vacuum line and switch the selector to hot, there should be vacuum in the line. If not, either the selector switch is bad or there is no vacuum to the switch. If there is vacuum at the line, but the flap doesn't move, the diaphram is most likely bad. You should be able to move the flap manually to make a temporary solution to this problem. As for the air conditioner, this almost has to be the vent selector switch at fault. Even with the air on, the heat should still come out warm. You can make the A/C stop by unplugging the two wire clip on the compressor.

 Rookie

Most likely the heater airmix door. remove the actuator on the side of the hat air box on passenger side floor ( it's white and is held with 4 screws Be carefull with the connector if you remove the connector but for now watch the arm whitch turns very slowly when you turn the heater control knob) if this turns ok your problem if probly the flapper door inside the unit.their know to break and DORMAN offers a replacement abort 40 bucks at auto zone or advance but to replace this find someone with experience with heater core removal. ford only offers a complete unit for aroun 250 bucks.