Member Since: 24 May 2012
Location: North Yorkshire
Posts: 1240
Is the Heated Rear Screen Always On?
Random and least important question of the day.....
Is the heated rear window always on in a low power mode even when it is supposedly switched off?
The reason I ask is that many times in cold damp weather like this, I've noticed that the rear window doesn't steam up in normal driving and the road spray landing on it seems to dry in stripes following the heating wires.
Does the window keep heating in a low power mode all the time, does it do it automatically depending on the temperature or is it just that the glass is a bit thinner where the wires are so the road crud dries faster from the heat escaping from the car?
It's not important, I'm just curious. MY2022 D5 HSE D300 - with extra nice bits added
MY2019 D5 HSE 3.0 SDV6 - sold to a dealer for a crazy price! - So good I bought another!
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19th Nov 2016 6:37 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
No but it does come on in cold weather for a preset time which will give it a temperature gradient for quite some time afterwards.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 15 Oct 2016
Location: Tromso
Posts: 45
Was just wondering on this myself
In cold weather the front and rear heated window is automatic activated on start up, and the manual switches light up.
I usually switch them of again on start up to save the battery, but it seems that the rear window is still on as any fog or ice on the rear window melts following the heated wires.
Is the heated rear window activated despite turning of the manual switch?
19th Nov 2016 9:44 pm
JonM
Member Since: 24 May 2012
Location: North Yorkshire
Posts: 1240
Indeed, I often switch off the screen heaters as soon as the engine starts, but the road spray can still be seen drying in lines on the rear window at the end of a long journey. MY2022 D5 HSE D300 - with extra nice bits added
MY2019 D5 HSE 3.0 SDV6 - sold to a dealer for a crazy price! - So good I bought another!
MY2012 D4 HSE 3.0 SDV6 - retired to a new home
19th Nov 2016 11:21 pm
Hairy Dan
Member Since: 19 Jan 2011
Location: Co. Durham
Posts: 12319
I've noticed it also on the rear screen.Cheers Ian
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19th Nov 2016 11:25 pm
Dannyson
Member Since: 15 Oct 2014
Location: Newquay, Cornwall
Posts: 820
Thats a very good question as it happens - as I've noticed the same.... 2016MY Discovery HSE - Black
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19th Nov 2016 11:41 pm
Pedros
Member Since: 25 Jun 2011
Location: Cumbria
Posts: 454
So, we're saying that in cold weather, when the heated screen automatically comes on when you start, that it stays on even when you select the button to turn it off? Curiouser and curiouser (to quote Lewis Carroll in Alice In Wonderland). I shall have to look out for that.
23rd Nov 2016 3:32 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
No.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 03 Jul 2009
Location: Glasgow
Posts: 6902
Agree it does look like it does, otherwise why else would this happen? Not part of the aerial is it perhaps?Joined the BMWX5 45e group
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23rd Nov 2016 7:55 am
blackbeltbob
Member Since: 07 Feb 2007
Location: Troon
Posts: 366
When mine was in getting a service I asked them about this. They said I was mad
But it does come on in the wet etc when not asked too.
Sooooooo is it therefore on all the time?
23rd Nov 2016 4:57 pm
JonM
Member Since: 24 May 2012
Location: North Yorkshire
Posts: 1240
Ok, after this evening I'm 93.2% sure that it does come on automatically despite Robbie's far greater knowledge than mine.
When I left my last job this evening, it had gone dark and the temperature had dropped whilst the car had been parked. I closed the boot, started the engine and drove off. The temperature displayed on the dash was 5°C.
The rear window heater hadn't come on when I started the engine and despite the rear window misting up I left it switched off.
After about 5 minutes of driving, the external temperature started dropping. It dropped from 5°C to 4°C with no change, the rear window was still misted up. Then, just before it dropped to 3°C, the rear window started to clear, the mist started disappearing from the glass at the heating elements and the clear lines expanded away from the heating element lines until the window was clear.
At no time were the heated screens switched on (not switched on manually and no indication that they had been switched on automatically).
I don't have the facilities to take any measurements to prove that the car was heating the window, but what I saw was very convincing and I can't think of another explanation.
Does anyone have a FLIR camera I can borrow to try to prove it? MY2022 D5 HSE D300 - with extra nice bits added
MY2019 D5 HSE 3.0 SDV6 - sold to a dealer for a crazy price! - So good I bought another!
MY2012 D4 HSE 3.0 SDV6 - retired to a new home
25th Nov 2016 7:50 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
I have a FLIR, but I only do serious technical stuff with it.
Click image to enlarge
Land Rover - Turning Drivers into Mechanics Since 1948
Last edited by Robbie on 25th Nov 2016 8:00 pm. Edited 1 time in total
25th Nov 2016 7:58 pm
Cobstar
Member Since: 03 Mar 2010
Location: UK
Posts: 194
My heated rear window comes on automatically and doesn't light the button to turn it on. Haven't checked what temperature or worked out if I can manually switch it off.
I hate this feature as I want to be in control of what's on.
The heating system seems to have a mind of its own in manual mode too. If I select a direction and fan speed that's what I want. Not a sudden decision to select all directions and air con.
25th Nov 2016 7:59 pm
JonM
Member Since: 24 May 2012
Location: North Yorkshire
Posts: 1240
Robbie wrote:
I have a FLIR, but I only do serious technical stuff with it.
I thought that was what they were invented for... MY2022 D5 HSE D300 - with extra nice bits added
MY2019 D5 HSE 3.0 SDV6 - sold to a dealer for a crazy price! - So good I bought another!
MY2012 D4 HSE 3.0 SDV6 - retired to a new home
25th Nov 2016 8:02 pm
rrhool
Member Since: 28 Aug 2014
Location: Norfolk
Posts: 4405
It's in your handbooks! Richard
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