The cabin air temperature sensor has a small fan that draws air from the cabin through the small grille in the lower facia, left hand side.
I think what you can hear is the small fan running on when it is supposed to be off. If this is the case it would certainly cause a battery drain.

SOUNDS as if it could be, its the right area; do you know if it has a dedicted fuse ??

bob

The fan isn't shown separately on the wiring diagrams, I presume it is an integral part of the air temperature sensor.
I'm surprised either of fuses 12 or 34 didn't cause it to go off.
It might be worth taking the dash section apart and disconnecting the sensor unit and see what happens.
As far as I am aware the small fan is the only thing that moves in that area that would cause a noise.

where is it actually located in the dash ?

What model year is your car?

The fan's behind the little grille which is part of the HVAC controls - on earlier models (up to 2005ish, I think) there was a known issue which this not shutting down and an additional loom was developed to "fix" the issue.

https://www.landyzone.co.uk/land-rover/bat...ss.275482/

Sometime later they must have fixed the original HVAC unit not to do this anymore and the harness become unecessary.

Depending on the year of your vehicle this may be something to investigate.

Other causes of that module staying on, well it's hard to say, I've seen suggestion of it being the FBH or possibly even door catches/bonnet catches causing the BCM (Body Control Unit) to wake up and wake up the HVAC system.

PS: I'm not a mechanic, just trying to piece things together from various forum posts!

BOBCUSSEN wrote:

where is it actually located in the dash ?

Hiding behind the big red circle on a 2010MY vehicle!

mine is 2004 vogue !!

In that case you may want to have a read through this thread and see if it helps: https://www.fullfatrr.com/forum/topic38061...yni500040k

Here's the relevant TSB (Technical Service Bulletin) which details it: https://fliphtml5.com/mbek/fxzi/basic

Includes the following VIN number range to see if your vehicle is included:
AFFECTED VEHICLE RANGE: New Range Rover (LM) 4A153466 to 4A164860

thanks i will take a look

bob , keep you posted

intersting about hevac fan Which will invesstigate, but feel my fan noise is more passenger footwell area, but just wondering, will car only go sleep with locked doors, or would it still sleep if you just took keys out of ignition ?

bob

No need to lock vehicle for it to go to sleep. However, just have to open doors bonnet or boot for things to spring back into life. It's a b"::;r for draining the battery. I can leave my car for 3 or 4 weeks with no problems starting or, if I'm doing any jobs involving multiple entries over the day then I have to make sure charger is connected! Previous cars:
S-Max 2007-2013 (only diesel I've had, good car but expensive when diesely bits go wrong, so what's the point?)
Galaxy 2001-2007
Mondeo Estate 1997-2001
Sierra Estate 1993-1997
Uno Turbo 1987 -1993
Fiesta 1984 - 1987
Fiat 127 1982 - 1984

hi martin, yes i imagine every time its 15/20 mins before things shut down again !!

i hope i can resolve this drain with the little fan behind the hevac panel, how important is it, i wonder if there is a controling fuse ? , 12 and 34 dont stop it !!

could you not just snip the wire to the fan ?

I wouldn't advise snipping the wire to the fan, you'd be masking the symptom rather than fixing the problem.

The fan itself isn't what's draining the battery, the problem is that HVAC ECU and possibly the BCM ECU is being kept awake and that's what's draining the battery.

You're looking for any fuse which is related to heating/cooling/blower motors etc.

(There's also fuses in the rear fuse box!)

Pulling Fuse 62 (10amp) in the front fusebox (A/C / HVAC) seems to stop the noise and kill the 0.2amp draw for me.

You can check it's the HVAC fan by putting your ear next to it, should be obvious. From a distance, ie: sat normally in the drivers seat, it's hard to distinguish the noise between the sat nav screen fan and this cabin air temp fan.

For me the sat nav fan shuts down after a few minutes but the HVAC one runs indefinitely.

The hazard warn switch backlight stays on regardless of the Fuse 62 being in place or not, so this is a red herring.

The backlight on the dash seemed to go off with the Fuse 62 being removed, thought it's currently bright sunshine so it's hard to tell for 100% certain.

So now I just need to work out what it is that's causing the A/C circuit to stay active, honestly, not sure what to check tbh. One thing I noticed is the catch on my lower glove box is broken, causing the light inside the glovebox to never come on. Not sure that would be related though as it's broken in a "permanently closed" position, not a "permanently open" position.

If you place a stamp sized piece of tissue paper over the little grill containing a tiny fan for the HVAC you should find it is held in place by the suction of the fan, when your turn off the engine and lock the car, after approx 15 mins the tissue should fall off indicating the fan has, shut down therefore no suction, if it remains in place then its likely the fan is, still running albeit silently and drawing current.. 2008 L322 Vogue 3.6 TDV8 in Java Black with parchment and Navy interior. 125000mls.

I used to be indecisive and have a split personality... but we are ok now...I think?