Heat blows cold. Climate control switch cold to hot in both positions it blows cold. Antifreez level is great. Truck doesn't overheat. Is it possible the blend door isn't opening I understand its is operated by another part blend door act. Which controls the blend door any help or suggestions. Thanks

 

If both heater hoses are hot , it's a good bet the blend door is broken.
You might want to check, HeaterTreater™