How does the heating/AC system work?

[eniacs]

Have had the E70 2012 40d for a couple months now and popped out the other night for some fishing. I went to put the heating on upon return as it was a bit cooler at night. The main vents (in front of the driver either side of steering wheel) didnt want to put out warm air however. The cabin did eventually get warm from the window and footwell outlets however.

Fast forward to today and I was in BMW for other things and asked for them to show me how the heating side of it worked. The service woman showed me to just put the temperature up to desired set point (obviously) turn off the AC (this is unlike my other BMW's which would put out warm dry air with the AC on) and then go into climate settings and put the drivers setting to warm. We then sat and waited and although the cabin did get warm, air does not come out of the main vents. She explained that BMW had found that the main vents producing warm air is likely to make the driver sleepy and so they dont make warm air, only cold.

Does this sound familiar to anyone else? My previous E46 would happily produce warm air from any of the vents in the winter, with or without the AC on and to the set point required.

Why would BMW decide to prevent warm air coming out of the vents like this? I immediately thought, why not make the seats uncomfy too, in case the driver falls asleep as they are too comfy...

[X5Sport]

I never turn the a/c off.  It's left on 'Auto' (push the left control and the light comes on) and the temp goes to wherever I set it.  I get warm air out of all the vents.  I can also set which vents to blow the air from, but
I leave it in 'Auto'.  The iDrive also allows me to set the rear temp to match the driver (I have 4-zone in mine).

Sounds to me like the BMW drone was talking tripe!

Our E46 can have different face vent temps by playing with the thumbwheel (as you know).

Richard

[eniacs]

Hi Richard;

This is my main issue, I think it should follow the set point I give it, Ie produce whatever temp air from all vents, but it doesnt. The main vents shut off whenever a requirement for warm air is set. All other vents produce warm air...

I usually never have AC off either, it makes a nice dry, sweat free environment in the car.

The addition in the E46 of the thumbwheel seems to be still present in the iDrive menu to adjust the vents of driver and pax to either hot or cold. But neither setting allows much air to actually flow through the main vents if heat is required.

Im starting to think the car has a fault, but my wifes 120d is the same lol so maybe is just me!

[kenniff]

I don't have my E70 any more, but when i did I could produce hot air from all the vents. I too never actually turned the "cooling function" ie the AC off.

On the Auto setting you would get warm air (if the car temp is below what you've requested on the dial) from all vents. You could change this in the idrive settings to your own manual configuration but those manual settings got wiped as soon as you pressed auto again.