2002 Corolla Turning the AC on when defrosting

Totally normal. The dry air clears the glass much faster. You can still set the temp to whatever is comfortable. The air does not have to be cold. It can be set to hot, and with the compressor on, the air will be plenty warm but dry. If the air is too cold, crank the temp setting up.

Totally normal. The dry air clears the glass much faster. You can still set the temp to whatever is comfortable. The air does not have to be cold. It can be set to hot, and with the compressor on, the air will be plenty warm but dry. If the air is too cold, crank the temp setting up.

Why be forced to run the AC in the winter? It makes no sense.

Actually on ours, the AC compressor button light is not illuminated, but it gets cold as hell very quickly so it's running.

Why have to waste gas on that? It's crazy, especially when we have a dry climate here anyway. ( this aint Japan )

I sometimes get out of the car when it's rained lightly and the ground is a little wet, yet I get popped by static from the seat. That's how dry it can be here.

It can be dryer here when it's raining than it is on a sunny day in Miami. ;-)

You're pushing the defrost button. As you can see, it plainly works.

AC is used to dry out the air, and that's generally required to remove the moisture from the windshield.

a) the system is intelligent enough NOT to use the AC when it's too cold outside

b) just because the AC is on doesn't mean you'll get frozen. The system can use both the AC and the heater at the same time. If you don't like the temp of the air coming out, simply increase the temperature some. You'll still get the benefit of the AC drying out the air, but you'll also get more heat from the heater at the same time.

This simply isn't a problem.

No, it's not.

But you don't want to believe how your system works, you think you know it all, so we're all wasting our breath here.

It makes perfect sense. If the windshield is fogged on the INSIDE, what you need is dry air. The best way to get dry air is for the compressor to kick in. At least 90% of drivers are incompetent, so this easy science concept escapes them. Toyota takes care of the problem correctly.

Actually, the compressor DOES kick in regardless of temperature in my 02 Tacoma. I can shut OFF the AC manually if I want to and it'll stay off until the next time I select defrost or start the car when the vent selector is in the defrost position.

Correct.

It may be cold but not cold enough to freeze someone.

For the last 35 years or so...

Could be.

There should be a knob or lever with a blue to red scale near it (sometimes they are actually labeled cold-hot but most people can't read anymore so they've resorted to easy to understand iconic labels) , this is the temperature adjustment, experiment with it and see if you can figure out that it controls the temperature of the air coming from the various vent outlets in the vehicle cabin.

Depends on the ambient temperature. Then again, circulating the oil in the AC system is a good thing and will increase the life expectancy of the compressor.

Automakers have been designing AC systems this way since the middle 70s, every once in a while someone comes along (approximately one in 20 million people) who can not figure out how to use the HVAC controls.

Kind of reminds me of the joke about the Pollack and the chain saw...

AC is supposed to come on when Defrost is selected. You can always turn the Temp Control toward the red area. There is no reason the heater cannot overpower the AC and blast out warm air.

Personally, I prefer to manually switch the AC on when I feel like it, not because I have selected a set of holes that I want the air to blow out of. Just because the air is coming out of the defrost ducts does not mean I am defrosting the windshield. I might just want fresh air to come out that way instead of having it blow in my face from the main dash vents.

My F150 is the worst! It has decided that any vent I select that isn't the dash vent or the floor vent is a demand for AC. I can select dash and floor as a combo, and that triggers the AC. How stupid is that?

At least 90% of drivers are incompetent,

Proving once again that JoeTooStupidForWords is full of crap.

Please provide the study data that proves your wild assertion.

No need to worry. The AC compressor won't run when the temperature is below

Besides, you can still run the tempearture control up to hot and get out hot air.

Ed

Actually, the compressor runs at any temp in my 02 Tacoma. Easy to tell while still idling in the driveway. When I switch to defrost, I get the same click from under the hood and the same effect on the tach as when using the defrost/AC at higher temps.

Might be different for her Corolla, though.

So your random observation is that everybody around you is an idiot, and you're not?

Your thesis is flawed at best.

Hey - you said you were no longer going to communicate with me. Stop being a pussy & keep your promise.

I never said that. Your reading comprehension is as bad as your writing comprehension. We've been over this before.

I'll bet you that the compressor does not run when the underhood temperature is below approximately 40 degrees F no matter what you think. All modern vehicle AC Systems incoprate either a thermal switch or a low pressure switch that inhibit compressor operation at low temperatures. I am sure your Toyota Tacoma includes a low pressure switch that inhibits the compressor engagement at low tempeatures (I think it is called a binary Pressure Switch - it switches off the compressor when the pressure is too high or too low - at 40 degrees, the pressure will be too low becasue almost all the refrigerant will have condensed). You might still hear a relay click, but I am sure the compressor doesn't run. If you don't have a switch like this, what do you suppose happens when your compressor tries to pump liquid refreigerant?

Ed

Beats me. All I know is what I observe, Ed: The sound, and the effect on the RPMs, which is identical to what happens in summer.