Climatronic fault

[Passatb6tdi]

Hi
I have an intermittent fault on my heater.
Sometimes it has just stopped working for a time sometimes the first 5 mins sometimes a day sometimes from turning off and on and sometimes from just pressing any of the buttons.
Sometimes when car is started and sometimes after it has been running and fan already been working.
All genuine parts, new blower fitted 6months ago.
New resistor and old one re fitted to check,
New relay, and is clicking still when not working
12v constant to fan makes it work fine,

When faulty, the recirc light doesn’t light red,
Button works when test/reset is done as this is one of the 2 buttons pressed but still doesn’t illuminate

Control panel all works fin it seems and shows all other lights and operations when fan not working inc the higher & lower fan speed lighting and temp lighting
Other buttons- feet/vents etc all seem to make motor noise when pressed and not working
In reset mode, all flaps sound to be operational and not noisy
It just sometimes doesn’t work then just all of a sudden will come on
It is a nightmare when raining and steams up the windscreen as it won’t clear and makes driving hard unless you put your head out the window like a happy dog in the summer breeze but not recommended due to safety issues and cold teeth.
Any help would be greatly appreciated.
It was scanned by a Vw Audi garage on snap on and vag com with no answers other than they don’t know other than poss control panel faulty but is newer one and they have never seen this type fail. Only older versions like b5.

[Passatb6tdi]

Sorry recirc button colour is orange not red

[Passatb6tdi]

Further to this, the heater was working properly today on hot.
I then put on fully cold on both sides and put on a/c to see if it worked,
It came through cold, checked pipes in engine bay and they were really cold and after 5 mins of the car ticking over the blower got progressively slower and slower over about 30seconds until it stopped working.
Now it doesn’t work again on any setting.