My 57 plate RRS has an "econ" button that turns off the air con whilst allowing the fan/temperature to be selected.

I've used it once to see how it worked. The car started to feel humid inside and the windows started to mist up so I turned the aircon back on and it stays on all of the time. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Just press button with Ac Big fun of RRS-my one WHITE-RED with wide body kit plus RS alloys all from KAHN

MY2012:-
With Auto on and AC on, press AC and it all goes off.
With Auto on and AC on, press Auto off and the climate control goes off, air con stays on and you can manually adjust fan speed.
or with Auto on and AC on, manually adjust the fan speed and Auto goes off.
Its all logical really...
Auto is automatic climate control, and can only work with air con on.
AC is air conditioning, this must be on for Auto to work.
Changing the fan speed manually overides the Automatic climate control.

Clear as mud. RRS MY12 SE Siberian Silver, Ocean, Ivory and Walnut.
3.0 SDV6 256hp, 8 speed autobox with flappy paddles, Factory fitted options: Privacy glass, tow pack, heated seats, heated steering wheel, RSE, centre cool box, premium carpets, mood lighting,vision pack and memory pack.

I know it's an old thread, but I took my 2011 RRS into the dealer yesterday (as I was in the area) to enquire about transmission shunt- normal for age and mileage apparently...
Anyway, also asked about the windscreen vents also going cold when the climate control is up to temp. Annoying, as I get a cold right hand from the falling cool air. The tech also said that the air con compressor is ALWAYS running, as it keeps the system lubricated etc. Pressing the AC button just moves flaps about and directs chilled air into the cabin. In one way, it makes sense, but is madness in all others considering the amount of fuel it sucks!!
Investigation to follow to see if pulling the AC fuse releases a clutch etc and can fuse be supplemented with a switch... You can't see the eyes of the demon until him come callin'

When I turn down fan speed or turn off Climate it does physically turn off A/C and this doesn't run unless switched on or part of Climate Control. The dealer is nuts saying a/c runs all the time, complete bull  John

RRS MY12 SDV6 HSE. Sumatra Black/Ebony & Walnut + Dynamic Pack, + Cold Climate Pack + Memory Pack, Digital TV/DVD, Premium Leather, Cornering Lights, Cooler/Fridge Box, & most Options.

I'm not so sure, I went to Milton Keynes and back today with the climate set to auto (AC light on too) all the way there and back. No discernible change to fuel consumption as you might expect.
The guy at the dealer is a proper tech, not a spotty sales boy, so knows his stuff- I hope. I'm going to have a poke around the engine bay and check the A/C pipes are always cold as he said and will report back... You can't see the eyes of the demon until him come callin'

Unless the pre-facelift car (pre 2012 SDV6 8 speed gearbox etc) cannot be turned off, and the MK2 (2013/14 onward) may be different again.
Climate on will automatically run with A/C on, it's when you physically turn it off, using switches or turning down the fan speed and the lights go off on switches, that the A/C is no longer running, the way you describe above is of course running with a/c on permanently. John

RRS MY12 SDV6 HSE. Sumatra Black/Ebony & Walnut + Dynamic Pack, + Cold Climate Pack + Memory Pack, Digital TV/DVD, Premium Leather, Cornering Lights, Cooler/Fridge Box, & most Options.

I have a 2012 RRS and auto only works with A/C on which I found strange after coming from a M3 where auto just seemed to control the fan speed to regulate the temperature but didn't mean A/C would be on unless you pressed the A/C button.
I have noticed that with the A/C and auto off my fan changes pitch like it is still being controlled somewhere regardless of what I set it to.
With winter here I find I have my A/C turned off as even if you turn it up to 28 you still get that chilled air draft from somewhere which disappears when A/C switched to off. 2017 SVR. SVO Scafell grey Ebony interior
2012 3.0 SDV6 Autobiography santorini black with ebony/cirrus interior. Gone