OK, I’ll do my best to describe it, as I see it.
In the aircon controls section choose “auto”. In every car I’ve ever owned with climate control (including 5 previous Mini’s) if the interior temperature is say 26 degrees centigrade and I choose a temperature of say 20 degrees the fan will fire up and pump cool air until the temperature is reduced to my chosen setting. Once the temperature reaches 20 degrees the fans slow down and will go up and down as required to maintain the temperature. However, in the new Mini it just sits there on the slowest fan setting never reducing the temperature. It’s pumping out cooler air but not fast enough to achieve its target temperature. So if you then go in to climate settings you will see there is an option for fan speed (odd, in auto mode, but it’s there). Now, if you change the setting from its default (very low) to “low” the fan instantly goes to maximum. All settings above “low” (medium, high and very high I think they’re called) appear to be the same speed - so you have very low or full blast. Now you’ve selected a faster setting the car cools down but the fan stays on high so just keeps getting colder. This means you are then forced to go into the settings again to reduce the fan speed - so then the car heats up again… and so it goes on ad infinitum! By way of a test, if I turn the temperature back up up to 26 degrees the fan just keeps going (at either full speed or very low depending on the selected option in the aircon settings). To get the cabin temperature to an acceptable level I have to put everything to manual and constantly adjust the fan speed. The fan speeds do work in 5 stages when in manual mode - but confusingly they are labelled 1 to 5 rather than very low to very high when in auto - go figure! So at least in manual mode you can have a medium fan speed.
It’s almost impossible to just set a temperature and leave it to it. Never had the problem with any other car with a climate control option, I typically set the temperature to 20 degrees and never need to touch the controls again throughout the year. With this car I’m constantly having to fiddle with the settings. I’ve just done a 600 mile round trip over the last few days and found the only way to get comfortable was to set aircon to manual with output restricted to face vents only and speed set to level 2 (sometime 3 if really hot) and then maintain cabin temperature by opening and closing the vents physically as required. There were four of us in the car and working together this was the only workable solution.
My dealer replicated the issue on their demos and stock cars. Whether they reported it to Mini is another matter as their feedback suggested they thought that must be the way it’s intended to be. I haven’t yet challenged them on it again. I may do in due course.
If I’m doing something wrong then so is my dealer - and we’re both following the handbook.
Interested in any feedback you may get.