On the XB the air conditioner goes on with the AC even if the AC button is not pressed even if it is cold out. This wastes gas.

The Scion rep says you can work around this if you put the defroster on then
move the temp to warm then press the AC button on and off it will turn off the AC

Otherwise the AC stays on - pumping hot or cold air even in winter - wasting gas.
I have tried his but can not tell if the AC stayed on. Anyone have any experience?
HOW CAN I TELL IF THE AC COMPRESSOR IS RUNNING? If its not set to cold the compressor can be running and not putting out cold air.

If I turn the temp **** back to cool the AC is on.

There are lots of situations when it just wastes gas to have the AC on
Especially when its snowing

This setup does not add any value to the car. Scion should allow the owners to select
if they want/need to use the AC in defrost mode.

On a cool day I was in the xb for 5 hours wasting gas while the
defroster forced me to use AC even when it was on the warm setting!

This is about the only flaw I find in the car! I do love the box.

 

Many car manufacturers do this, for example Ford, it is because for most parts of the country, people do not run the A/C in the winter months, and to keep the compressor from being unused for 5 months, they find a way to be able to have it kick on to keep the system operable all year round, furthermore, if your windows fog up inside, a little trick is to use the a/c to help de-fog them faster, whether the temp control os on hot, or cold. Yes it does waste a little more gas, but I would rather use a little more gas when my car is on defrost, then have my compressor lock up in the winter due to no oil circulation.

Anyone else have any other input?

 

Yeah, running the A/C also removes humidity from the air, heeping the windows from fogging up.

 

Exactly...it would take forever to de-fog a window if you didn't have the ac going. The fog is caused by the warm air on the inside of the car mixing with the cooler air (and glass) on the outside. Only when you equalize the two will it clear the window.

 

When you turn on the defrost the AC is supposed to come on. However, it should turn off when you move the dial from defrost to a non-defrost setting.

 

I would not worry about the fuel consumption, as the AC compressor we have is pretty high efficiency (ie. low power consumption)

You're better off with it on, as you'll get quicker defrosting.

In my old Tercel, I'd turn the AC on when defrosting for this very reason (and that *wasn't* a high efficiency compressor ... I had to turn off the AC to accelerate sometimes!)

 

There was a time - like a few years ago when the AC did not come on with the defroster. I am aware the dehuidification capabilities of Air conditioning. Thanks again.

Now back to the question. How do I turn off the AC while in defroster mode and verify the compressor is not running and just producing heat and reducing gas mileage when AC is not called for.

 

You don't.

 

I've not poked around under the hood yet, but once you follow the procedure that the Scion rep told you, leave all your settings as is, then open the hood. If our compressor is belt driven, the pulley should be turning, but the center of the pulley will not (ie, the clutch should be disengaged.) If our compressor is electrically driven, you'll probably have to tell by sound.

Set your controls to something other than defrost, and turn on the AC. Note the change in sound. Turn off the AC, and follow the Scion instructions. If they do indeed turn off the AC, you should note a change in sound.

However, the amount of gas consumed by having the compressor running is very small. Deprive yourself of one of your favorite small treats (coffee, soda, candy bar) for each tankfull of gas and you'll have more than made up for the extra gas burned by the AC.

 

I don't have A/C on my winter car, so you can imagine it's impossible to defog the windows when it's raining or snowing.

 

Air conditioner definatly kills gas mileage if windows are closed. And in cool weather heat will defrost just fine. Running air conditioning without allowing the owner to turn it off is wasteful.

 

I drove a rental Pontia Sunfire a couple of months ago. In that car the light on the AC button came on when you turned the defrost on, but you could not turn it off no matter how many times you pushed the button. It is normal and as far as I know, almost every car works that way and gives you no control.

 

as said before, 100% normal!

Im still getting 33MPG in the city, WITH my defroster on the whole time.......

 

I know that this is normal and even what I excect, however, I'm not sure mine is working correctly. The AC light is not coming on when in defrost mode. Are others seeing their light turn on? If so I need to get this looked at, just don't want to go to the dealer if it is not coming on for others and look like a !

I did try one thing last night just to see what the diff was in the recycle air vs vent air. The defrost setting sez to use vent air with def (if I remember correctly), I ran it with recycle and it didn't want to defrost very well, fliped to vent air and it instantly cleared. So I guess we should just follow the directions, sometime a groups of engineers/car designers are smarter than the average driver.

And as far as AC killing the MPG, I drove all summer with AC on (avg 31.5mpg) and once fall came and I turned it off and started driving with windows down my MPG DROPPED to 29.5-30 mpg! So I'm guessing that running the AC IS NOT using MORE gas and being wasteful!

 

the ac light does not come on in the car when the defroster is in use. but trust the ac is on.

 

One additional tidbit: I don't believe the A/C compressor on the xA/xB has a clutch, but instead has an electrically adjusted swash plate that varies the compressor displacement from zero to max to control it's output: in other words, the compressor shaft is ALWAYS turning when the engine is running, but the compressor is not always 'compressing.'

As to using only outside air, at max A/C or max heat positions (and for three or four clicks away from those positions) the controller also opens the recirc door so the unit is pulling both inside and outside air for most efficiency. (See the Service Manuals for details.)

 

Ther are some conditions where AC will provide better gas mileage certinaly not all driving conditions. I hope you are not implying that!

It is true if you drive over 50 MPH with windows closed and the AC on you will get better gas mileage. Under 50 keeping the AC off and windows open provides better gas mileage. However if you drive the same speed with the windows closed and no AC you will get the best gas mileage! This is an obvious fact and a little research will support this fact.

All things being equal the AC does drain power from the engine and does hurt gas mileage. This is a pretty simple fact of life. It takes energy away from the wheels and puts it into making cold air.

I am referring to cold days when one would have the windows closed and the temp setting to warm. The driver should have the option of turning on or off the AC in defroster mode.

Also some have stated incorrectly that the heat defroster will not be effective with out the AC - this is also incorrect. Defrosters were working just fine for decades before AC was an option. I agree there are times one might want AC in defroster mode. But a choice is all I am asking for.

I live in the north east where New England winters can be quite cold and running the AC is wasteful and yes - it does impact fuel mileage. I prefer give the fuel companies a penny more than I have to!. They are making record profits as it is.

 

Wow. Chicken Little called. He wants his sense of proportion back.

 

umm, they tested the air conditioning on/off vs. windows open on Myth Busters.
zero difference.
myth busted.

 

Myth busters is where I saw the info. They re tested the windows open and found that below 50 its more efficient with windows open and over 50 it is more efficient with AC.

I saw the broadcast in early October of this year.