HVAC No Airflow

[Pinger]

The good news: with the aid of the above photo, I freed my stuck vent door.
The bad news: when it freed the spring thing flew apart. And doesn't look like it wants to go back together. One step forward, two steps back...

More two steps forward, one step back...
Got the linkage for the face vents reconnected and all seemed fine - briefly. Then I couldn't get flow at the screen demister and when I looked at the actuator not much was moving. Disconnected the face vent link thinking it is binding (or I re-assembled it incorrectly - probable) and the actuator is moving again in line with mode selector. It also moves when the blower setting is changed. Is that normal? Is it merely the air flow pushing on the doors - or something more sinister?

 

[ChRoNo16]

When I was working on mine, i also used some WD40 on each of the spots that looked like they were originally lubed to free them, worked wonders it will help to start with that, and when we did lube them we just kept changing the mode so they would move and lube themselves free

 

[AK49BWL]

More two steps forward, one step back...
Got the linkage for the face vents reconnected and all seemed fine - briefly. Then I couldn't get flow at the screen demister and when I looked at the actuator not much was moving. Disconnected the face vent link thinking it is binding (or I re-assembled it incorrectly - probable) and the actuator is moving again in line with mode selector. It also moves when the blower setting is changed. Is that normal? Is it merely the air flow pushing on the doors - or something more sinister?

No, the mode door actuator should not be moving with the fan speed switch changing... Unless you turn off the blower in which case it will move to the center (floor only) default position. If the doors are in fact sticking, it could be as simple as blasting a little white lithium grease at the ends where the door pivot points go into the box, and on the spring assembly.

 

[Pinger]

No, the mode door actuator should not be moving with the fan speed switch changing... Unless you turn off the blower in which case it will move to the center (floor only) default position.

Thank you kindly - that clears that up nicely. Returning to the centre position when the blower is turned off is exactly what it does.

If the doors are in fact sticking, it could be as simple as blasting a little white lithium grease at the ends where the door pivot points go into the box, and on the spring assembly.

Not sticking - just a problem with the connecting link to the face level vent door arm. See here >> https://www.gmt400.com/threads/hvac-control-weirdness.63909/