turn off the A/C for window clearing in winter?

[Weidehopf]

When the heater direction dial (right-hand of 3 dials) is set to 'up' position for windscreen clearing, the A/C button lights automatically. This is not very useful in winter when the screen is iced up - want warm air to defrost the screen. Is there any way to disable this function?

Otherwise greatly enjoying the Yeti on the icy roads of Germany with superb Goodyear Eagle 8's 205/55 R16s .... just waiting for first snow to really try it out! :yes:

[eccleshill]

When the heater direction dial (right-hand of 3 dials) is set to 'up' position for windscreen clearing, the A/C button lights automatically. This is not very useful in winter when the screen is iced up - want warm air to defrost the screen. Is there any way to disable this function?

Otherwise greatly enjoying the Yeti on the icy roads of Germany with superb Goodyear Eagle 8's 205/55 R16s .... just waiting for first snow to really try it out! :yes:

If the outside temeprature is very low (below 4 degrees C I think) the air con doesn't operate no matter what the indicator lights say.

[bgw]

When the heater direction dial (right-hand of 3 dials) is set to 'up' position for windscreen clearing, the A/C button lights automatically. This is not very useful in winter when the screen is iced up - want warm air to defrost the screen. Is there any way to disable this function?

Otherwise greatly enjoying the Yeti on the icy roads of Germany with superb Goodyear Eagle 8's 205/55 R16s .... just waiting for first snow to really try it out! :yes:

I have found on previous cars that using the A/C clears any condensation on the inside well before the temperature is hot enough to defrost the windscreen or clear the condensation with warm air.

I always use a de-icer or warm water to get the ice off as it is also much quicker.

On my new car I have ordered the heated front windscreen and I hope that this will be a ritual from the past :-).

[Moist Von Lipwig]

As long as you have the temp set then it shouldn't matter whether AC is on or not for the heat. What AC does do is get you drier air so that it will clear up any fogging on the inside.

[eccleshill]

I have found on previous cars that using the A/C clears any condensation on the inside well before the temperature is hot enough to defrost the windscreen or clear the condensation with warm air.

I always use a de-icer or warm water to get the ice off as it is also much quicker.

On my new car I have ordered the heated front windscreen and I hope that this will be a ritual from the past :-).

I hate de-icer! It reduces the temperature of the windscreen massively and ensures that any water on the inside becomes ice. I only ever use it as absolute last resort.

Warm water! Next door neighbour used to use that until one exceptionally cold morning he poured it over his windscreen and the thermal shock cracked it from side to side. He thinks it may have been due to a chip that had already weakened it but still a helluva risk!

[JCP]

The air conditioning only cools the air when set to a temperature below the car's interior temp. So no harm at all in using it and it won't interfereb with the warming up of the car. It will de-mist well. The aircon will not operate in very low temps to protect the mechanism.

[Llanigraham]

Both my Freelander's did exactly the same and it was brilliant at "de-fogging" the screen, and I found the Yeti was just as good last winter.

[KenONeill]

As #3, 4, 6 and 7 say, air con delivers drier air to the screen, so it demists faster than the heater alone will.

Also, if you don't have aircon, the screen clears faster if yu turn the heat off until the the engine is hot!

[rockhopper]

As above, the air con does not work below 4 degrees. Don't worry about it. I leave mine on all the time as mentioned above, it stops the car from getting fogged up inside.

[bgw]

I hate de-icer! It reduces the temperature of the windscreen massively and ensures that any water on the inside becomes ice. I only ever use it as absolute last resort.

Warm water! Next door neighbour used to use that until one exceptionally cold morning he poured it over his windscreen and the thermal shock cracked it from side to side. He thinks it may have been due to a chip that had already weakened it but still a helluva risk!

I must admit I have never seen the issue of water on the inside becoming ice because of the de-icer - surely if the outside was frozen it would be frozen on the inside as well already? It takes too long for a diesel car to produce heat to defrost thick ice so if I cannot scrape the ice manually I use it.

Regarding warm water - it is just that - warm - I have only heard of a screen cracking when a boiled kettle was used - but as you say, it may just have been weakened by damage -and I would not knowingly use water on a damaged screen myself - and as you say - as a last resort. Still better than driving with a 'porthole' like some people do.

[EZ_lo]

The usefullness of warm water depends greatly on how cold it is really. If it is cold enough you will end up with a thick layer of ice on your windshield.

(tried once to wash me car with a bucket of hot water and guess what - could do some ice skating on my roof afterwards )

[cooliospoolio]

I think you'll find that the reason the AC kicks in when you use the screen clearing setting is that one of the things AC does is dry the air as well as chilling it (when below a certain temperature). Dry air is much much more effective at clearing condensation off the screen than blowing "ordinary" air at it.

[Babs]

It's more effective and quicker to clear the screen with dry air of a similar temperature. To defrost the windscreen from the inside with hot air will take forever.

Is this your first car?

[speedsport]

And back to school physics experiments....

The surface of hot water freezes more quickly than that of cold water - because of accelerated evaporation. Honest!! :wonder:

Try it sometime - put two similar containers outside when it's well below freezing (or use your deep freeze) with an inch of water in each, one cold, one hot & see which one gets ice on the surface first!!!

To clear ice on a glass surface where the ice is usually starts a thin film of condensation, you need to raise the temperature of the glass, hence the use of the heater to keep it frost free.

Edited 17 November, 2011 by speedsport