Adjusting the climate control

Sorry Chris..i did not realize that you were referring to the Defrost button.

Your elaborate explanation about how the climate control works helped me in understanding its workings. To be frank and contrary to public perceptions, the Prius is indeed a sophisticated car and a marvel in car engineering. Thank you for all the help.

 

Tom,
My wife just did exactly what you said about setting the temp after pushing the Auto button. And it works. She was telling me that her ride to and from my son's school was pleasant with the car being warm. Thank you for your help. I could have figured this out very late, may be days later, but your timely suggestion saved a lot of frustration.

 

Air is always going through the microfilter, regardless of setting.

When you push the button, the system switches from wherever you had it to run its program as I described above. After the program completes (30 sec - 3 minutes), the system reverts to whatever setting you had previously.

 

One other observation: this morning I found it necessary to defog the front windshield. After much gnashing of teeth whilst driving into the sunlight, I realized the fog was exacerbated by the windshield itself being dirty on the inside. You don't realize how dirty that window is on the inside until you properly clean it.

 

Correct. It is trying to process as much of the inside air as possible without being overly obtrusive.

 

I read an explanation on here that said that even when you have the mode set on recirculate that the outside vent door does not completely close, always allowing a small amount of fresh air. When you go to filter mode, the outside vent door closes off tightly forcing only the cabin air through the cabin air filter to remove any dust and pollen in the cabin.

My filter mode timer is 3 minutes then it reverts back to Auto mode and whatever vent mode that Auto is calling for at the moment.

 

My observation is the defrost function will only use the air conditioner if the Front Defrost button is activated. If the Mode button is used to direct air toward the window it displays the Defrost symbol, but it does not activate the air conditioner. It does not work well as a defrost (defogger). In order to keep my front window from fogging on winter days, I have to use press the front Defrost button. It will auto select fresh air source (you cannot over ride which makes sense).

My Prius seems to be more fog prone than previous cars I have owned, maybe the large front window is a factor.

I wish the car had a way to toggle the temperature reading from outside to inside. I am more interested in the interior temp.

 

Hi All,

Here is how I use the automatic controls in the winter. I have auto set to 65 F. Typically, I arrive at the car, and its well below freezing. I scrape the windows (park outside) start the car, and hit the front panel front and rear defrost buttons. Which disables the Auto function, and directs air as previously detailed in this thread. When I can see sufficiently out of the car , I proceed to drive away. Now the cooling condensor is not being used at this point, as the action is to defrost, not defog, and the interior temperature and dew point are such that only heating will clear the windows.

After some time driving (about 5 minutes) the windows are completely clear, and the temp is close to 65 F. I turn off defrost, and the car switches to AUTO when turning off the Defrost button.

Most trips, that is it.

But, with multiple passengers, and longer trips eventually the windows will begin to fog. When this happens I hit the defrost button again, and the system uses the cooling condensor to remove humidity. This happens pretty quick , and I then turn off the defrost button. Over time, the car then starts using the cooling condensor automatically to dehumidify the interior air, and it switches the vent air fraction automatically.

 

One point that might help those with windshield fogging problems:

When the inside of the windshield is dusty or dirty, or covered with condensed volatiles from interior fabrics/plastics, fogging can be much worse. If you are a smoker it can be really bad. Clean the glass with a quality glass cleaner to minimize the fogging problem.

 

Hi Arthur,

This is so true. I use Stoner brand "Invisible Glass" to get that tough Polyurethane sealant film off the interior of the windows.

 

The "auto" function is supposed to be a general solution to most climate. It is however pathetically inefficient against window fogging, this with experience from two major swedish carmakers which both has solved this problem. One of then even detects "fogging condition" and turns on electricaally heated read-window for a preset time.

Apart from this inability to de-fog, the auto function in both prius II and III is "all you ever need"

 

Yeah, I wish the stock display would show interior temp too. I have one of my four ScanGauge slots set to the XGauge that displays interior cabin air temp.