Focus mk3 climate control problem, or am I imagining it?

[All that jazz]

I'm fairly sure when I first got my mk3 ST fitted with the so-called dual zone climate control that the fan speed would automatically adjust itself when twiddling with the temp dial. It doesn't seem to do it anymore, but I'm beginning to wonder whether it ever did it . For example, today it was 12C when I got in my car (from cold) according to the dash read out and the leather seats felt a bit chilly initially so I dialled the climate up from 22C where it was last at, to 28C. I was expecting the fan to wake up and pick up speed but it did absolutely fk all. It is already in AUTO mode according to the display so it should adjust the fan speed as it sees fit.

The only way I can get the fan to go all balls out in AUTO mode now is by dialling in either "HI" so it's on max or by dialling in a really low temp. Making any smallish adjustments between those points doesn't seem to alter the fan speed whereas I'm 99% sure it used to do it. The fan would be trying to match the temp you've set as soon as possible so even if you only adjust it by a few degrees it would increase the fan speed accordingly to give you the temp you asked for.

I've tried it with aircon button both on and off but it doesn't make any difference. The side and centre vents are fully open as per the handbook operating instructions.

To those of you who have the same automatic climate control system, what does yours do if you dial in 29C on the climate display when you have an ambient temp of mid teens on the dashboard AND the engine is cold? It just seems wrong that the fan does feck all when you're asking it to give you 29C of toastiness. (I am of course fully aware that one is not going to get 29C of toastiness from a cold engine but I'm fairly sure the fan used to go all balls out and at least try.)