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How to activate Recirculation mode in defrost mode?

4930 Views 9 Replies 7 Participants Last post by  tteuvky1
In my corolla 2008, when i use defroster to defrog windshield the ac turn ON and i am not able to use Recirculation button, the air come from outside, i know it is design that way so windshield can be cleaned more faster.
My question is, is there a way to activate Recirculation mode in defrost mode? like it is possible in Honda civic i guess
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I don't think it's possible.

When defrosting, fresh air helps get the moisture out of the cabin. When recirculation is turned on, it just uses whatever stale air is in the car.

My 2012 Mazda won't let me use recirc while defrosting. It will shut it off when I select it.
I found this online:

"The defroster automatically and forcefully turns on the A/C and blows in outside air. Unfortunately, it knows better than you and you have no choice.

The designers figured 99% of the time blowing fresh dried air is the optimum way to defrost the windshield and getting complaints like yours is better than getting complaints from lots more people who leave the recirc button on and can't get their windshields to defrost quick enough."

"Outside air, especially on a cold day, is always lower in humidity than what is inside the cabin, because you're inside, presumably exhaling. That's why the windows fog up in the first place."

"...the defrost is also a dehumidify. As we get in and out of our [cars] in the winter we drag snow and ice into the cabin with us, adding to the humidity factor. As we where taught in school the recipe for steam (mist) is water (ice) and heat."

"I was under the impression that if the outside temperature is cold enough, or the temperature of the evaporator approaches freezing (32F), the ECU will disengage the A/C compressor clutch. This is to prevent ice from developing on the evaporator, and both blocking the airflow and stressing the A/C system.

If this is the case, then when the outside air temperature is below freezing, the compressor might not be running as much as we might be assuming here.

But when the outside temperature is above freezing, and especially when the outside air is damp, (e.g. rain, foggy conditions etc), the added dehumidifying effect of the A/C will have a significant benefit."
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There was a lawsuit years ago against Honda, I believe, regarding fogging windows. I think, it stuck to their bones so much that they - lawyers - forced defogging as priority onto designers.
Sucky part is, in cars that go shaking with AC one or, AC is literally causing led ball power reduction, the very moment you turn anything to windows, you lost chunk of your engine power.
This is why I have window visors on my cars. Just crack 'm open, create a fresh air circulation, be happy.
Its possible, but counter productive, not sure why you think it is safe or worth your time. Guide below shows you how to decouple AC and recirculate.

The reason for it is just stupid useless laws, you can easly remove the a/c controls and in the back there is a little piece of plastic that forces the recirculation to be off when you select he windshield defrost, this forces the a/c to turn on as well, you can simple remove this little piece of plastic and then you will be able to select circulation air on any setting, while people argue the best setting is outside air and it should be forced i have situations where I have to remove ice and if the car is getting air from the outside instead of outside it just takes longer, other times for example when i have a big large 4x4 truck in from of me and windshield is fogging I can just push the reciculation without worrying about being smoked by the truck.
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