Heated Rear Windscreen

[MrUkSkodaDriver]

Hi All,

Just bought a 280 L&K. I love the car but one thing I find strange is that the Heated Rear Windscreen takes ages to demystify. I think it may be taking 15-20 mins to do so. Is this typical of the 280 L&K ? The front heated windscreen is wonderful and the back seems very slow.

 

Any responses appreciated.

 

[Danny 57]

Welcome.

 

Three things.

1. Are you talking about the mist (dew) on the inside of the car or the dew on the outside? The mist on the inside is condensation as is what is on the outside anyway.

2. If it is what is on the inside then make sure that your rear window is clean on the inside as this does slow the de-misting down significantly. The internal mist will be much less in content than the outside.

3. If it is the outside then it will take a lot longer as you are trying to evaporate the external moisture. Not a quick solution.

 

Btw if you have a lot of condensation inside then you may have water in the footwells, otherwise you should not get much at all internally.

 

Disclaimer.

The above might just be b......s.

 

 

[themacster]

Maybe a silly question, but is it actually working, I.e. do the wires actually energise?

[SiBo777]

On this... what about 50% defrost capability?? I’ve heard of a dropped element but not dropped half a screen? Upper section was rapid to clear. Thoughts please...

[penguin17]

It was -6 this morning and my car had been stood since around 1530 yesterday.  It took about 2-3 mins to completely defrost the rear screen, maybe 1-2 mins for the front.  I've always found the front screen clears much quicker but I suppose that's down to the efficiency and full coverage of the heated windscreen tech Vs the traditional, spaced out elements on the rear screen.   

 

If it's taking over 5 mins and/or not clearing the full screen then you likely have an issue somewhere.  I would start by giving the inside of rear window a good clean and maybe put a moisture trap on your parcel shelf too.   If you can rule out residual moisture then the elements would be the next thing to investigate. 

 

Also check your boot for signs of leaks or damp, the spare wheel well is worth checking too.   Do you have a sunroof? 

 

 

Edited 31 January, 2019 by penguin17

[J.R.]

1 hour ago, SiBo777 said:

On this... what about 50% defrost capability?? I’ve heard of a dropped element but not dropped half a screen? Upper section was rapid to clear. Thoughts please...

That will be a scratch running through the upper elements.

 

I have some conductive paint that I bought 40 years ago to repair open circuit elements.

[MrUkSkodaDriver]

1 hour ago, penguin17 said:

It was -6 this morning and my car had been stood since around 1530 yesterday.  It took about 2-3 mins to completely defrost the rear screen, maybe 1-2 mins for the front.  I've always found the front screen clears much quicker but I suppose that's down to the efficiency and full coverage of the heated windscreen tech Vs the traditional, spaced out elements on the rear screen.   

 

1 hour ago, penguin17 said:

If it's taking over 5 mins and/or not clearing the full screen then you likely have an issue somewhere.  I would start by giving the inside of rear window a good clean and maybe put a moisture trap on your parcel shelf too.   If you can rule out residual moisture then the elements would be the next thing to investigate. 

 

 

 

Thanks penguine17. The rear windscreen is very clean and the elementses do appear . I'll try to put a moisture trap on your parcel shelf too to see if that helps. 

[MrUkSkodaDriver]

12 hours ago, themacster said:

Maybe a silly question, but is it actually working, I.e. do the wires actually energise?

Thanks themacster. Yes, the element are visible and do energise.

[MrUkSkodaDriver]

15 hours ago, Danny 57 said:

Welcome.

 

Three things.

1. Are you talking about the mist (dew) on the inside of the car or the dew on the outside? The mist on the inside is condensation as is what is on the outside anyway.

2. If it is what is on the inside then make sure that your rear window is clean on the inside as this does slow the de-misting down significantly. The internal mist will be much less in content than the outside.

3. If it is the outside then it will take a lot longer as you are trying to evaporate the external moisture. Not a quick solution.

 

Btw if you have a lot of condensation inside then you may have water in the footwells, otherwise you should not get much at all internally.

 

Disclaimer.

The above might just be b......s.

 

 

Thx Danny 57. It's the mist on the inside of the rear window. The car is < 6 months old and there doesn't appear to be any water in the foot wells etc.

 

 

[2BeFrank]

Do you run the car with air con off and internal air recirculation on ? (rather than fresh air in)

[MrUkSkodaDriver]

40 minutes ago, 2BeFrank said:

Do you run the car with air con off and internal air recirculation on ? (rather than fresh air in)

I've only had the car for about a week did not put the air-con on. I've just put the heating on without the recirculation option.

[2BeFrank]

Well if there is moisture within the car, I suggest you run the aircon (with a good warm temp  throughout the car) and WITHOUT the recirculation.

 

Should help draw out any residual moisture, and get it out

[Adrian55555]

Yep air con should be used all year round. Even in the winter but with it on a heat setting. Aircon systen acts as a dehumidifier so draws out liquid from the cabin. This increases the speed windows will demist. Plus it keeps the aircon system lubricated. 

[IsoE]

Can confirm that rear window heater will melt ice/snow at -25C (-13F) in maybe two minutes, so it most definitely is powerful enough to remove mist.

[MrUkSkodaDriver]

14 hours ago, IsoE said:

Can confirm that rear window heater will melt ice/snow at -25C (-13F) in maybe two minutes, so it most definitely is powerful enough to remove mist.

 

Thanks IsoE. The current weather will make for a good test of this

[MrUkSkodaDriver]

21 hours ago, Adrian55555 said:

Yep air con should be used all year round. Even in the winter but with it on a heat setting. Aircon systen acts as a dehumidifier so draws out liquid from the cabin. This increases the speed windows will demist. Plus it keeps the aircon system lubricated. 

I didn't know this so that's useful. I've set it as you've mentioned and will monitor the HRW to see if this improves things.

 

It may be that the HRW was having to do a lot of extra work due to excess humidification within the cabin etc.

[MrUkSkodaDriver]

22 hours ago, 2BeFrank said:

Well if there is moisture within the car, I suggest you run the aircon (with a good warm temp  throughout the car) and WITHOUT the recirculation.

 

Should help draw out any residual moisture, and get it out

Yup. Will try that. Thx.

[Adrian55555]

55 minutes ago, MrUkSkodaDriver said:

I didn't know this so that's useful. I've set it as you've mentioned and will monitor the HRW to see if this improves things.

 

It may be that the HRW was having to do a lot of extra work due to excess humidification within the cabin etc.

Yep the gas in the system lubricates all the rubber seals in the system. A lot aren't aware and this is why a lot of people who only use aircon when we get a bit of warm weather find out its broken.  Mine is on all the time. But even if u use it once a week it will be better than leaving it off for most of the year.