Mr Vlad

Rear Screen Demister

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Sorry if this has been brought up before but on your is300h do all the elements work in the rear screen to demist? 

I've noticed that the top 4 of mine don't work leaving a 3-4 inch band of humidity on the screen. 

I'm just asking as a kind of census. 

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The top few lines on mine seem to be on a separate section, I believe they are antennae for the radio.

Certainly was the case on my previous cars... 

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Mmmmmm if that' the case that would explain it. I didn' think about that section being the radio aerial. Cheers pal.

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i have mine on all time this season it seems it is just not powerful enough!

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May be damp in the boot.

Found a design fault this week. Opened the boot with snow on the lid. Snow slid onto back window, then into the boot.

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3 minutes ago, PaulWhitt20 said:

May be damp in the boot.

Found a design fault this week. Opened the boot with snow on the lid. Snow slid onto back window, then into the boot.
 

I think I'd class that as operator error :wink3:

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17 hours ago, dutchie01 said:

i have mine on all time this season it seems it is just not powerful enough!

I noticed mine also doesn't seem to be as powerful as on some other cars I've driven. Maybe it's an economy measure. Does the rear screen stay misted if you have the air conditioning on, too?

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Mine defrosts very well but is less successful at demisting .. 

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Mine appears to be spot on....no complaints and very quick. However it appears to take precedent over the heating system / fan......or is all the juice going to the lovely heated seats.

The whole thing is still a complete mystery to me..is it a safety thing that windows getting cleared are a priority over cabin temperature ? I have no idea.

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Talking of demisting. On my car the rear demists quickly. It takes a little longer to clear exterior frost tho.

However the only thing that bugs me about my car is demisting the front screen. 

To clear the front screen takes approximately 12 or more presses of 3 different buttons.

My last 4 fords had One button to clear the screen in literally seconds.

Why oh why has a top notch manufacturer of cars decided to have an archaic method to clear the windscreen.

Oh and don' reply with there is one button to clear the windscreen. I press that. Then I press the fan speed to max then I slide the temp to max

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If I recall correctly, Ford developed a heated front screen and patented it so other manufacturers couldn't copy it.  I may be wrong, but I recall reading that somewhere.  My front screen takes a few minutes to clear using conventional fan method.

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I keep one of the small dehumidifier bags in the car and that has helped reduce the misting a great deal.

My biggest issue is defrosting, which a heated windscreen would solve. Yes, I believe this is a Ford patent. Not seen it on any other model of car. 

Not keen to use deicers or similar, so it's scrape and heat till glass is warm enough to prevent any more water re-freezing. Anyone got any better ideas? 

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14 hours ago, Mr Vlad said:

Oh and don' reply with there is one button to clear the windscreen. I press that. Then I press the fan speed to max then I slide the temp to max

Sounds odd that you need to do that. If my climate control is on auto, when I press the demist button the air is directed to the windscreen and the fan speeds up automatically. The windscreen demists quickly. I wonder why your fan doesn't speed up automatically. Is it because you've changed the fan speed from the auto setting? Or is the air conditioning turned off?

Or maybe the fan speed only increases when the engine has warmed up a bit. But that seems unlikely from what the RAC website says (mentioned in a link above) as even cold air will help.

Another factor of course is that the screen should be clean. In days gone by, before air conditioning, people would wipe the windscreen to get rid of mist. But that just made it worse by putting specks of dust on the windscreen that the mist would stick to.

Might be worth checking the air conditioning is working properly.My experience is that the whole car mists up if the air conditioning is turned off in wet or cold weather.

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Excellent point Thackeray. I'll check the settings  (I'm sure they'e on manual )

The ford demister is a windscreen fitted with 000's of ultra thin wires which in conjunction with the fan demists the screen in literally seconds. As to it being patented I'm unsure. I'll find out .

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27 minutes ago, Mr Vlad said:

As to it being patented I'm unsure. I'll find out .

It is.

 

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My wife has a Ford Fiesta and it has the Quick Clear windscreen, cracking (no pun intended) bit of kit, I've had a Mondeo before with it too.

One feature my Saab(s) had was to automatically put the heated rear window on and turn the climate control to windscreen demist automatically when the temperatures were low and as the interior temperature increased, it then gradually eased the fan speed down and ultimately ended up back on the normal auto settings.  Now this was 20 years ago, something a prestige car like Lexus should have in its feature list, the only thing I had to do was turn the heated seat on when I had my commute starting at 6.30 in the morning, many times I didn't even venture back out of the car to clear any frost, the car warmed up quickly and a warm seat is much better than going back out into the cold.

So far I've found the Lexus clears then windscreen with reasonable speed though, I only ever press the demist button, then disengage it when its done its job, no need to touch any other buttons for fan speed or temperature settings.

 

Vince

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Well I asked on the ford forums I'm still on and the patent ran out 2-3 years ago and is now used by a few other manufacturers.

I've changed the setting to auto so I'll see the difference in the morning at 4.30am and report later tomorrow. 

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It'll be interesting to hear what difference you find if you have climate control set to auto before pressing Demist. Hope it makes a difference.

One other point to bear in mind is that the manual says: 

"Operation of the air conditioning system in Eco drive mode
In Eco drive mode, the air conditioning system is controlled as follows to prioritize fuel
efficiency:
● Engine speed and compressor operation controlled to restrict heating/cooling capacity
● Fan speed restricted when automatic mode is selected".

So, as well as auto climate control, check that the car isn't in Eco mode - ie switch to Normal or Sport - before pressing the Demist button. 

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Thanks William. As it happens I only drive in either eco or sport when I want to be silly lol. I'l switch to normal and see what happens and report back. Thanks again. 

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I use a method thats probably frowned upon, but as I park outside my house, I use a 10 litre container of warm water (tepid not boiling) and just go over all the windows. its quick and have never cracked a windscreen throughout ownership of cars. However my old Clifford Alarm had remote start and 5 mins of the car running outside all windows are generally clear :-D 

 

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Well William as I stated I would I'm reporting my findings. 

I switched to auto and then drive to normal. I then started the car then pressed the demist button and hey presto 1 click to demist.

Thanks pal. Oh. It works in eco too as I tried it whilst at some lights. The fan sped up to max.

Happy bunny now.

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On 16/12/2017 at 9:25 PM, steveledzep said:

If I recall correctly, Ford developed a heated front screen and patented it so other manufacturers couldn't copy it

They did but thank goodness. I drive Ford hire cars and loathe looking through the wire elements which to me are clearly visible. No thanks rather have a fan & a clear glass windscreen!!

 

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