Member Since: 12 Oct 2012
Location: Poole
Posts: 54
Automatic Climate Control without Air Conditioning
With previous cars it has been possible to turn off the airconditioning pump but still allow the climate control to adjust the temperature, fan and vents. Although the handbook (page 60) says that depressing the A/C button does this on my MY2012 D4, in practice both A/C lamp and the AUTO lamp extinguishes and I am sure the fan speed never alters thereafter. The heating system seems to fall back into manual mode. Is this correct?
16th Jul 2015 10:41 pm
caverD3
Member Since: 03 Jul 2006
Location: Oberon, NSW
Posts: 6922
Press ECON button?“There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely gamesâ€
Ernest Hemmingway
D4 3.0 Active Diff, Adaptive Lights, High Beam Assist, Surround Cameras, Privacy Glass.
D3 2.7:Adaptive Headlights,Electronic Rear Diff,ARB Bar,Blaupunkt Speakers,JVC Powered Subwoofer,Removable Snorkel,Mitch Hitch,Pioneer After Market Head Unit,Steering Wheel Control Adaptor,Remote Adjustable Supension Rod System, Taxside Dual Battery System.
16th Jul 2015 11:29 pm
discoteca
Member Since: 08 Mar 2010
Location: Warwickshire
Posts: 1477
What Econ button, OP is talking about a D4 not a D3?
17th Jul 2015 7:40 am
Kilovolt
Member Since: 29 Jun 2015
Location: South Derbyshire
Posts: 1020
There is an A/C on/off button on the bottom edge of the rotary dial which controls fan speed. Press once and the orange LED light goes out and at the same time the AUTO led light will extinguish..... but it will still allow fans to run and it will try to control temperature using either the heater matrix or out outside cool air for cooling demand (assuming it is colder outside than it is in the car).
Turning the fan spped dial anti-clockwise with several quick 'flicks' will shutdown the fans and heating/cooling system completely. Useful if you want the ignition on for a little job but don't want the fans going flat-out. Just press AUTO to re-start it."Track day running - Don't put your foot back on the accelerator until your absolutely sure you don't have to take it off again"
Current Ride: D4 XS Commercial Baltic Blue SDV6 fully loaded with heated everything
Track Days: BMW E36 M3 Evolution MY 1996 (3.2 Litre 377 BHP sat in 1,250 Kgs of car, with a pro safety cage and some serious braking power)
17th Jul 2015 7:48 am
Rixy
Member Since: 12 Oct 2012
Location: Poole
Posts: 54
Thanks. Because the AUTO light extinquishes naturally I thought that the climate control function had been switched off like it is when you alter the fan control. In that case to re-establish the AUTO fuction you press the AUTO button and the lamp illuminates (which brings in Air-conditioning even if you don't want it.)
So with the Climate Control in operation sometimes the AUTO lamp is on and sometimes it is off. Just one of those Land Rover quirks.
17th Jul 2015 10:24 am
viethson
Member Since: 13 Jan 2009
Location: Bavaria
Posts: 136
As mentioned the Auto function will continue to operate even when the Auto light goes off when the AC button is pressed. I think the reason the Auto light extinguishes is that the system cannot 'guarantee' a proper climate control without being allowed to use the AC for cooling. But when outside temps are low enough the Auto function works just as it should even without the AC (with both lights off)Life in the slow lane
18th Jul 2015 6:54 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
On the D3 and D4 turning the aircon 'off' does not fully stop the output of the AC compressor, it just outputs at a low level in order to keep the system healthy.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Oct 2012
Location: Poole
Posts: 54
Robbie, on my SAAB the AC pump was isolated from the engine drive belt by a clutch mechanism behind the pump pulley. On the Land Rover therefore if the pump has to be kept turning slowly there must be some sort of viscose or fluid coupling which is overriden by a clutch. Interesting.
19th Jul 2015 10:27 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
There is no real clutch as such on the D3 / D4 design and the pulley on the end is only a torque limiter and effectively a dumb pulley.
You have the right idea over the control that is used instead but rather than using a fluid or viscous coupling to vary the speed the drive remains linked to engine RPM and the pump displacement and output volume is varied instead by pistons acting on a rotating swash plate. The piston travel is controlled by the PCM via a PWM signal.
With zero output the swash plate is in this neutral position:
Click image to enlarge
To achieve the maximum output the pistons drive the swash plate to a more acute angle (please excuse the fingers):
Click image to enlarge
I hope that makes sense, if not I can clarify a little further. It is a very neat design and provides minimum drag on the accessory side of the engine and has proved to be exceptionally reliable. Indeed, it is a truly excellent bit of kit.
Land Rover - Turning Drivers into Mechanics Since 1948
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