Okay the issue that is going on is this all settings work no leaks or smells blows cool air and then heat works after about 45 mins after driving. Temp gauge in middle normal am guessing. Then seems to get cool again temp gauge moves a little does not over heat. Changed thermostat did not help hoses into firewall hot to touch. The only thing i can find is the temp control **** is the only thing that is messed up very loose feeling not like the **** is working then grabs hold to work could this be the root to the issue? not moving the door actuator for heat? I do not hear door moving to close or open.

Anyone come across this before? Any help would be great thanks

 

Do a search for "Blend doors" this seems to be a common theme on these trucks.

 

Read a lot on this problem and discovered the answer to this particular ford. Heater blowing slightly warm air, thermostat was changed, no change. Discovered no power at cool/warm selector, and realized at the same time the daytime running lights were not working. Changed the 15 amp fuse for DRL and wouldn't you know it the heat selector has power, which operates the motor that moves that pesky door. Hope this helps someone else!

 

Cool, glad you figured it out, I will keep that in mind.