Welcome to 2CarPros. And welcome back:
This is an interesting issue because the when you increase the temp, the blend air door actuator is what should react. When you change direction of air flow, there is a different actuator which should respond, the mode door actuator. I think what we should start with is the mode door actuator. What I would like you to do is disconnect it and see if changing the temperature still has an affect on air flow direction. If it does, then we will need to inspect the mode door itself.
The mode actuator is located on the HVAC box under the dash. If you look at the attached picture, I highlighted both the mode door actuator and blend air door (air mix) actuator. You can see they are not close. That is what is causing me confusion.
Regardless, if we find air flow changes after the mode is disconnected, we will have to inspect the door and make sure nothing is loose or disconnected.
Let me know what you find.
Tuesday, December 1st, 2020 AT 10:46 AM