Cabin air vents not pushing out air?

The airflow direction is controlled by the mode door actuator. On this vehicle, it is actuated by an engine vacuum.

When you switch from floor to defrost, does the air flow change direction?

I attached a vacuum schematic below and highlighted the actuator in question. Let me know if you can control the other airflow directions so I know which way to go.

Also, with the engine running, pay attention for any air sounds or hissing sounds when you select the vent doors.

Take care,

Joe

See pic below.

It sounds like the mode actuator is not working because you have a vacuum leak under the hood in the vacuum feed line.

Here is a guide to help you fix it:

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

Please go over this guide and report back.

Blower motor is working on all speeds but no vents are letting the air out front and back. I need to check it up by the windshield to see if it is stuck on defrost. I did check the setting but did not hear any air coming out but did not feel if air was coming out by the windshield. If it is stuck on defrost then I need to know what specific part to get and where to find and replace the former one. Note: I did just now check on the defrost vents and they seemed to be working. The other ones are still not working - minimal air comes out no matter what the blower motor setting. The vents leak enough that I can tell that I can get either heat or cold. Thank you so much for your help with this. I have a CarQuest, O'Reilly's, and Napa auto parts store in my area.

Thanks so much for sending the diagram of the vent air flow system of doors. It really helps my understanding. Although the vents do not blow air they do let a little of the air to flow out from the heater or air conditioner. When I switch the control knob from cool to warm the temperature of the air changes which seems to indicate that the problem may be 2 doors stuck closed, to the floor cabin vents and one to the other cabin vents. The door to the windshield is open. So, maybe the blender actuator is working but the other doors are not.
I do not know where or how to fix or replace those 2 stuck doors.
Thanks again so much!

Thanks so much for sending the diagram of the vent air flow system of doors. It really helps my understanding. Although the vents do not blow air they do let a little of the air to flow out from the heater or air conditioner. When I switch the control knob from cool to warm the temperature of the air changes which seems to indicate that the problem may be 2 doors stuck closed, to the floor cabin vents and one to the other cabin vents. The door to the windshield is open. So, maybe the blender actuator is working but the other doors are not.
I do not know where or how to fix or replace those 2 stuck doors.
Thanks again so much!

You can remove the vacuum lines to each door and use a hand vacuum pump to test each one before you remove the HVCM unit.