The airflow direction is controlled by a vacuum-operated mode door. There is a chance the vacuum is weak, there is a small leak, or the actuator is going bad.
If you look under the dash, there are two actuators to look for. One is the panel/defrost and the other is the panel/floor actuators. I attached pics below.
Here is what I need. First, pay attention to see if there is any airflow from a different location when the panel is selected. If there is, the first pic is the panel/floor actuator and the second is the panel/defrost. Focus on the one that seems relevant.
If there is no air coming from a different location, with the engine running, see if you can hear a hissing or anything that could indicate a vacuum leak.
Let me know.
See pics below.
Images (Click to enlarge)
Saturday, August 6th, 2022 AT 9:53 PM