Blend door seems to be improperly locating. When on AC, everything works great lots of air in the proper places and cold. When winter got here this year, my heat is there, but only when activating the recirc switch. When I go anywhere else, mainly to defrost there is no heat whatsoever. I have pulled all the actuators (3) all work great and the doors are all working solid. I can only get heat to the defrosters if I pull the uppermost (left side from driver) actuator and manually turn it clockwise then reattaching the actuator "unplugged" thus allowing the recirc to be on and "Heat" to move thru the defroster....
At this point I can only conclude its in the dash climate control (which is only s single, not split)...Any clues anybody? Sure don't want to rush out and buy a new controller. I have pulled the controller to look at the circuit board but found no heat related spots or loose solder connections (those I have had on a sebring I once owned).. Other than that I'm at a loss......

 

I remember you have to learn the actuators if they are replaced. I don't know if pulling them is the same. You need a high end scan tool to see if the module "sees" what position the controls are calling for. If it doesn't "see" it than the controls are bad. If it does see it then you have a bad actuator.

For the low heat are you full on coolant. Are the heater core hoses hot?

 

There's lotsa heat....I know about "learning" the actuators and as far as I have found throughout the internet world that only relates to 2016 and below. Mine is a 2017 and all actuators are the same PN. I have moved them around, aligned them to the arrows/dots placing the into position in the blend door alignment mark with Identical results to placing them into the blend door in any ole position. Best I can tell they learn every time they are energized.
Thanks for the reply. I have updated my thread to explain a bit better and what I have done to achieve defroster heat. I deliver RV's across country and last week was a 4deg trip across WY, UT, ID, and OR. Scraping ice from the inside of the window is no fun, especially when trying to drive.

 

Ok so you don't have heat unless on recirc. That's a cooking issue. Low on coolant, thermostat, water pump, or heater core. Do any work recently to the cooling system?

 

6.7 Cummins. It uses no water, never runs hot even pulling toy haulers. Over the mountains pulling hard it never gets passed 225-230 but stays at 192-197 the majority of the time. Nothing done under the hood other than prescribed maintenance.
Is it possible that the climate controller may be the problem? The issue is not so much the recirc I believe. It seems to be more of air direction. I get plenty of heat out the vents, but when switching to defrost, the recirc opens and all heat disappears

 

i have this exact samething as you mention , mine act funny when cold like in the morning first start of truck , if i want in face direction or feet , it is not working , it stay like in a defrost state but i can't switch to face , i hear the moving door blend , but as soon temperature is up to normal , like 190 i can switch to where i want no problem ? mine is a 2016 3500 that i upgrade the factory 5 inch to 8.4 radio with bezel and hvac etc... i usually set on automatic ,