There is not a heater control valve on your vehicle.
1. Are both heater hoses hot? If one is cold then the heater core may be glogged. Most liley you have a problem with the temp blend door motor/actuator.
2. Is there any noise (clicking/popping) from the dash when you switch the heater control from hot to cold then back to hot?
3. Check fuse #5 (15 amp).
The problem is going to with the temp control switch or temp blend door motor. You are going to need a digital volt meter to perform some test. Do you have a volt meter, and do you know how to use one? Or you can take a guess and install a new temp blend door motor.
Check the items listed above, and let me know if you want to perform some diagnostic routines, or if you instructions on how to replace the motor, or both.
This will take a few e-mails to resolve this issue, but I can help you until you concern is resolved.
Removal
All vehicles
View Full Image WARNING: To avoid accidental deployment and possible personal injury, the backup power supply must be depleted before repairing or replacing any front or side air bag supplemental restraint (SRS) components and before servicing, replacing, adjusting or striking components near the front or side air bag sensors, such as doors, instrument panel, console, door latches, strikers, seats and hood latches. To deplete the backup power supply energy, disconnect the battery ground cable and wait at least one minute. Be sure to disconnect auxiliary batteries and power supplies (if equipped).
Vehicles equipped with floor console
Remove the RCM and bracket assembly.
Vehicles equipped with rear airflow duct
Remove the electronic blend door actuator.
Installation
View Full Image WARNING: The tightening torque of the restraints control module (RCM) retaining bolts is critical for correct system operation.
ASE Certified Technician
Ford, Lincoln, Mercury Technician
Install the blend door motor, and check the opertion before you put everything back together. If it works good then reinstall all removed parts if there is still a problem then reply and I will walk you though some diagnostic procedures.
Also, check to see if the blend door is binding when you have the actuator removed.
Chris
Most likley you have a door ajar switch that is sticking, the trick is to find which door it is, sometimes you can cure the problem by lubricating the door latches with wd-40, the switch is attached to the door latch. After lubricating the latches open and close the doors several times and see what happens.
Is your truck a reg or super cab?
Let me know if this helps, if not then we will have to remove both door trim panels and access the door ajar switches.
Both of your concerns are typical for your vehicle (10 years old).
I will take some time on Monday to give you some steps to check the temp control switch and blend door motor.
How is it going? Have you had a chance to work on your F150? I have been busy with snow and work, so I have not had a chance to follow up with you. Let me know if you have done anything yet