Air conditioning is on when defrost on.

Gee...that's like saying "How can I prevent hot air blowing when I turn the heater on".

When you want to defog your windows you need dry air else you'll merely fog them up worse so when you select defog the airconditioning comes on to dry the air and let it remove condensation from your windows...simple wot?

Reply to
Gord Beaman
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I have discovered that in my 2004 Sienna van that when I put on the defrost that the air conditioning turns on. Here I am like an idiot driving down the highway with all the windows open, defrost on, and air conditioning the world.

Now I know why this is, e.g. keeps the seals and system well oiled etc. But it was one of the things that really bugged me about the fords. I hate using more fuel when I don't need to and I do conscientiously turn on my air conditioning at least once a week for about 10 minutes winter and summer to keep thing running smoothly. Does anybody know how to disable it so that it is not on when the defrost is on.

thanks.

Reply to
Macdonald

Personally I doubt it will make any difference to global warming, but you could: Add a switch across the line to the compressor clutch, or the sensor for low pressure.

Reply to
mrcheerful

Gord, Im not sure if you have ever driven a car w/out AC. For 30 or so years I drove cars that never had A/C. I have never ever, ever had my windows frost up in the winter because I didn't have A/C. and "dehumidified air" blowing on them.(I live in the north with lots of cold and snow) Some genius in the car world decided that we must have A/Ced air to defrost with. Perhaps for some its necessary. I have never had this problem. As I say it has work for me for years. Infact I have the opposite in the summer when I turn on defrost to get fresh air w/out it blowing on me it puts condensation on the outside of the window. Anybody heard of that. This sometimes happens in the evening when temperatures are changing. Its like condensation on a glass of Cool Aid. The cold air blowing on the windows causes the humid air outside to condensate. I think the aggravation is that I would like the option to have it or not. The manual as I recall doesn't mention that the AC comes on when defrost is on. Nor does the AC light light up to tell me that. With Gas prices and pollution increasing. I should have the options to save both. Imagine the

1,000's or millions of people who may just leave their defrost on by default no knowing the expense it is costing them.

Does anyone know if there is a way to disable this feature?

Reply to
Macdonald

The truth is, that's got nothign to do with why they have the A/C on in Defrost mode.

The A/C is a dehumidifier, and when the Defrost is on, you want all of the dehumidifying you can get. There is no reason to disable the A/C when the Defrost is on, the A/C isn't the drain on fuel efficiency it once was. I don't quite get why the Defroster would be on while the windows were down -- where I live, if the windows are wet on the inside, it's cold on the outside.

Reply to
Jeff Strickland

While I agree -- to a point -- that you should have the ability to select the A/C independently of the other life support systems, I do not agree with your concern that there is an adverse environmental impact. Over a thousand miles, the A/C will suck up less than 10 gallons of gas. You actually use more gas with the windows down than with them up and the A/C on.

Set the Life Support to defrost for the first few minutes of driving, then switch over to the Vent settings to get fresh air in the cabin. Or, leave the Life Support set to defrost and forget about it.

Reply to
Jeff Strickland

For future reference, more automakers switch the A/C on with Defrost than don't.

Reply to
Jeff Strickland

Thanks I will have to look at the electrical running to the AC.

It appears there is no simple way. Ford actually had a jumper that you could change behind the dash. Pain to get to.

Reply to
Macdonald

Sure have...I'm 71 and I've been driving since I was

16...humm..55 years?

Me too.

Not really necessary I suppose but it stands to reason that it'll work better (and it does)

Sure, common logic son.

Ayup...

Sure it does...at least I've never heard of one that didn't. What makes you think that?

Reply to
Gord Beaman

I have a Sienna and an Echo. Neither one has the AC light come on when the defrost is on.

-Tom

Reply to
ToMh

I really didnt want to turn this into a long winded who and wherefor kind of thing I was really just asking a question to get the answer. I didnt want it to be like a political debate. But a few comments.

Sometimes the defrost is on just because it is left on from the last time you used the car. So its on needlessly. Sometimes I have turned it on because I want fresh air and open the windows a few inches as well but not fully because you dont want to be blown away. A car is a personal thing and everyone is different and until the communists come to power or bush has more power I think we can have the air flow we want.

Your comment on "You actually use more gas with the windows down than with them up and the A/C on." Actually up to about 2 weeks ago I believed that ( although this is definitely not true sitting in traffic, it was only considered true on the highway.) HOWEVER, Myth busters had a show that proved that that is not true. That Actually AC does consume more gas than leaving the windows open. I had to eat my words because I had said the opposite for years.

As far as pollution and Gas. You may be right it may be a small amount of Gas used with AC and it may be a small amount of Pollution caused by it. But small amounts add up with many cars. And Im going to say even a small amount of prevention is a good thing and a step in the right directions.

Thanks for you comments.

Reply to
Macdonald

Well, I sit corrected then...never heard of that...sorry boys. My son has a 04 Sienna so I'll check to see if his does. I know that my wife's 04 Matrix does and my sister-in-law who lives with us and drives a 05 Corolla does plus my 00 Corolla does...

Do you know whether the A/C is actually on or not then?

Reply to
Gord Beaman

Depending on your speed, of course. The faster you go, the more advantageous it is to have the windows closed. Puttering around in town, having the windows open is more efficient.

Reply to
dizzy

Just a guess here, but I suppose he lifted the hood and looked.

Reply to
Jeff Strickland

I saw the same episode of "Mythbusters." Actually, the vehicle with the A/C on and the windows up got better mileage than the vehicle with the A/C off and the windows down. They were doing their test with Ford Expeditions, BTW.

Reply to
Truckdude

But that was computer measured MPG. If I recall, they then put the same amount of gas in both SUVs and the windows down, A/C off SUV ran longer before using up the gas. So take your pick, I guess.

Reply to
Truckdude

I'm pretty sure it is. It blows pretty cold when in the defrost position. Mine are both 2000's, maybe they changed it by now.

Reply to
ToMh

Yes this is quite normal and greatly improves defogging of windows. WHen it gets below 40 or so outside, the low pressure limit switch will disable A/C so it will not be running in the dead of winter.

Reply to
SnoMan

Yeah, man I live in Mass and know what you're talking about. I also know last night I turned the defrost on and it did JUST what Gord said: got MUCH foggier before it got clear. I LOVE driving in 80 degree weather with the HEAT blasting to clear the windshield!

Look for the setting with the little defrost icon and an arrow blowing towards the feet. Use this setting.

I believe it is the ONLY way to accomplish what you want. Aside from disconnecting the AC Compressor, of course!

I will try to find out if there is some secret way of turning off the air. Remind me in the morning!

Reply to
hachiroku

Fords have been doning this since the early 90's, and there IS no way to turn it off on a Ford.

Reply to
hachiroku

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