Have an intermittent fault that is really annoying! - the air distribution (and heating) on my 2007 Landie keeps going off with no air coming from vents, the fan is fully working and can be heard - every now and again the system seems to reset itself and will work for a period of time (from a few days to several months) then just stops - does anyone have any ideas as to what is causing this??

Sounds like the actuators that open the vents are sticking. Now at the point when I learn something new something old is lost out the other side !
Now retired so it doesn't matter anymore.
Freelander now gone.

Had a idea that might be the case and you've just confirmed it - know what you mean about the old bit, pretty much me as well - thanks for the heads up

A diagnostic on the HVAC system normally tells you which servo isn't functioning correctly.
A quick spray of WD40 on the suspect servo will normally get it working again.

As for resetting. Each time the key is removed, the flaps close to prevent damp air from outside entering the vehicle. It sounds like sometimes the flaps aren't opening once the ignition is powered on again. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Thanks - have you any idea how to reach the offending parts?

Could be the HAVC module is up the duff