Defrost.

[barryware]

Originally Posted by Racer X-8

There's nothing to keep you from running the defroster with recirculated air. The fresh / recirculate selector just flip-flops a flap mechanically and there's no interlock or anything to keep you from flopping it over to recirculate while you have it set on defrost. I know for sure because I was just a minute ago filp-flopping it back and forth while it was blowing in the defrost position. Air came out of the defrost ducts at the windshield, nomatter whatever the fresh / recirculate selector was doing.

And, the graphic is just that - it's a graphic. It's recommending to you what to do, just a recommendation...

I was also making sure that the AC stays on when you have it blowing in either of the two defrost positions. It does not matter what you do with the AC pushbutton with the little blue light - the AC stays on while defrosting. I had the hood up and I could hear the compressor turning on and off. It stays on in the defrost positions nomatter what you do with the AC pushbutton.

Sorry I had to disagree, just stating the facts.

I understand that you don't HAVE to do anything. You can run your defroster anyway you want. Next time it is cold and rainy or snowy out, set you heater for recirculate.. It will only take a couple of minutes for you windows to start fogging up. It has to do with dew point which is directly related to moisture content and temperature of the air. That's why they "recommend" to use the fresh air setting.

As far as the compresser goes... No, it does not run automatically when in defrost. That is a fact at least on mine. I have had to turn it on manually on the 50 degree days when it is raining out. My light is green, not blue. Maybe the blue light models are automatic. If it is cold enough out, it won't run even with the switch on. The low pressure side if the refrigeration circuits pressure is too low to allow the compressor to run. That's why the compressor "cycles". When the low pressure reaches a certain temp (pressure in this case as they are directly related), the compressor "cuts out". When the low pressure sides pressure rises to a given pressure, the compressor "cuts in".

So There!

My Yaris is red... Red is the fastest color!

[Racer X-8]

Originally Posted by barryware

... My light is green, not blue...

Aw crap! You got me there! Mine's green too (had to go out there to make sure). Shoot. When did they stop using blue? Oh! Well! . . . You win

About your AC compressor cycling, if I read your bantering correctly, you need to have it checked - seems like it needs a re-charge of freon.

Oh, and, yes, red IS the fastest color. It adds at least 10hp to your car. Oh, yeah!!!

[barryware]

Originally Posted by Racer X-8

About your AC compressor cycling, if I read your bantering correctly, you need to have it checked - seems like it needs a re-charge of freon.

Oh, and, yes, red IS the fastest color. It adds at least 10hp to your car. Oh, yeah!!!

Dude... I didn't mean to "banter". I would usually let it go. But..... You are wrong telling me I am wrong.

I am a certified, registered, licensed, type III universal refrigeration technician.

I may not know anything about refrigeration but I have seen it a couple of times on TV.

Automobile AC system do "cycle". The compressor turns on and off via low side pressure. Keeps the evaporator from freezing and the high pressure under control in the extremes of an automobile application.

AC in a car is exposed to conditions that a home AC system or your refrigerator will never see. They will cut out on high pressure too but only as a safety measure. It is the low side pressure switch that regulates the evaporator temperature.

Point is... That a cycling automobile AC application is completely normal and does not mean that the system needs freon. According to what I have seen on TV

With that said.... Lets not forget that I am also the guy that over filled the crankcase on my first oil change... Oops