Okay I'm at my wits' end with this.

After about 10-20 minutes of driving, the air just stops blowing through the vents.

Troubleshooting steps I've done:
1: Filter swap
2: Pulled blower to check function. Functions.
3: Pulled some sort of thermoresistor in-line. This unit has cooling fins. Air passes through there.
That indicates to me that the blockage is somewhere further downstream.

Is there some sort of flapper valve downstream that's failing? If so, where is it so I can resolve issue?
When I unplug the blower connection and plug it back in, the air SOMETIMES starts flowing again, which indicates to me that there's some voltage related flapper somewhere downstream that's preventing airflow.

Wat do?

 

Don’t know your year, but in general there is a flapper (actuator) that controls the airflow. How this blend flapper is driven likely depends on your year. What I am familiar with are ones that are driven by vacuum control. There is usually a safety fallback concept, at least with US Cars, that defaults to defrost mode. Some are easy to get to and repair, and others (Fxxx) can be a pain in the rear.

My daughter’s Outlander thad an issue with temp control, which is aligned with this, and it wasn’t difficult to resolve. I know this doesn’t answer your question, but it is all I can offer and I couldn’t stand seeing your post with no response. Best of luck!!