Chrysler Repair: 2002 Sebring heater prob


Question
I'm working on an 02 Sebring 4Dr NO heat problem.  
- I have good experience on auto issues
- I verified intake and exit heater hoses are HOT
- I verified with eyes and air blowing, bled doors work and actuators work
- I verified heater core is clean by eyes, small hole in plastic structure
- I back flushed heater and water flows verified
- Heat is non existent !!!!
- I suspect external cold air vent is open, I have eyes on the vent door and it goes to outside air when the heater is on
So, the question(s) is could this be part of the problem, is this a known problem, how can I force the air to be recirculated internal?  or any other cause?    
Thanks for your experienced opinion.  John.

Answer
OK good work up till the cold air vent  no such thing.
Test your theory   whats the temp of the outside air and inside air? Also turn on the rec door when the ac on  does the fan blow harder air? and when u turn it off rec does the air pressure change?  if so  then  not a stuck door. And besides  if that was the case the rec door having any bearing on the temp inside  then it would always haft to be closed because u have no way of determining the  temp outside and changing it to what you want on the inside  with a manual knob system.   What you have s a classic clog in the heater core.  Its not a clog with no flow  its a clog with no way for the heater core which is metal to absorb and release the heat into the air that is passing through it by convection.