Heat and AC

You can set it to Auto without the potential for AC to come on by going to climate and hitting the yellow "AC". It should then go grey yet still perform climate control.

 

I think you will find that it's outside air you're feeling, which on 32-40 degree mornings is cold.

Thats one of my complaints with the Prius climate control. Once the car gets to the desired temperature, it blows out cold air. I end up angling the vents away from me and then it's OK.

 

The only time the compressor should come on when it's cold out (lower outside temperature than the desired cabin temperature) is when you put on the windshield de-fogger (the button that sort of looks like air blowing at a fan). If you have fogging windows, running the AC compressor helps reduce the humidity of the air blowing against the windshield, which helps eliminate the fog on the inside. Both the heat and AC are running then.

Otherwise, I agree with Marlin. It's probably outside air that hasn't been warmed that you're feeling. Try putting the system in recirculation mode and see if you notice the blast of cold air.

 

I know that you can set it to grey, but why does it come on initially. My garage is 46 degrees, I back out and the temp is 34 and the a/c is yellow.

Is there some initialization going with the computer system?

 

The yellow light doesn't necessarily mean the compressor is on, just that it is enabled. Exactly when it decides to use it (and at what speed) is a mystery known only to the system designers.

 

"I often feel cold air coming out of the upper vents."

Right, that is the way it is designed work. The A/C icon is a misnomer it actually denotes whether the Climate Control is functioning or not.

Denso says:

"By using a 50/50 ratio of fresh and recirculated air we were able to reduce the ventilation load 50%. At the same time, we were able to achieve the same cabin temperatures possible with conventional systems. Warm cabin air has a high moisture content. So, simply recirculating the cabin air would fog up the windows. The new system sends recirculated air out at foot level. Drier fresh air flows near the windows, which prevents moisture from condensing on the glass. "

For more info see: http://www.denso.co.jp/AR-e/1998/TW/climate.html

 

Thanks