OK. The heat does not get warm no matter how long the truck is benn driven or sitting. I have read all the posting on others that have no heat either, and some have helped but I will give you my scenario. We have changed the heater core, replaced the radiator, the blender door is working fine, hoses are hot to the touch. We have not changed the t-stat yet. What else could be the problem.

Please help.....

 

Does the blower fan even work?

 

As the post above said... Is it even blowing air? Also, is the temp gauge always cold on the truck? Or is it sitting in the middle where it should be. Don't go replacing parts in hope that it will fix things. That is the most expensive and the worst way to do it.

 

I guess the simplest thing to do is make sure that the temperature selector is set to the reddest part of the dial.

If the thermostat is stuck open or has been removed the coolant may never reach a temperature that will make the heater feel "warm". What does the temperature gauge read?

If both heater hoses are getting hot, that would indicate to me that hot coolant is flowing through the heater core and the problem is inside the blend door box or blower. If one heater hose is hot and not the other, it would indicate to me that the heater core is plugged or the coolant level is low or not reaching optimum temperature.
The blend door hinge failure is a somewhat common issue.
The blend box could be full of rodent nest which could be blocking the airflow. You haven't said if the blower is working or if it is diverting air to the different vents.

What makes you think the blend door is working fine? You can't see it unless you take the box apart or cut a hole in it behind the glove compartment.
This video describes the "hack" method of blend door repair using the 2 piece blend door and also gives some good basic information about how the system works and how to check it.
Even if you have tested the blend door motor to make sure it works, the door itself could have a broken hinge allowing it to swing freely. Although if this were the case you would most likely get heat randomly as the truck bounces around.

Please post more information about this issue.

 

Well if your hoses are hot, you are saying both input and output hoses from your heater core right? then your thermostat most likely doesn't need replacing, so don't bother. At this point it's one of the following:

1. Blower Not working
2. Blender Door really isn't working? (how did you verify that it was working?)
3. Controls are dead
4. A blown fuse (Confirmation that there is a fuse for the A/C and Heater?)