Operating Climate Control in Auto

When you press auto...it should turn on the a/c. Yes automatic is just like the thermostat inside your house...you set a temperature and the system will blow hot/cold air...whatever is necessary to maintain your selected temperature...

 

Based on my observation - Prius preferes to blow high volume air (and produces big airflow noise) instead of switching A/C on and lower air volume. The car also prefers the driver face vent direction when ambient temp >15°C. The fuzzy climate control logic can be better.
The 2nd gen Prius has and humidity sensor, but I don't know if this one is deployed for 3rd gen.

 

Turn on AC.
Turn on Auto.
Set the temperature that you'd prefer.

Should work perfectly.

 

This is on page 277 of the manual, and I think the bold phrase I highlighted clarifies that you need to press A/C to get the compressor to come on. It reads a little like some early Japanese camera instructions, not stated very clearly:

n [FONT=Arial,Arial][FONT=Arial,Arial]Using the automatic mode [/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]Fan speed is adjusted automatically in accordance with the temperature se.-ting and ambient conditions. As a result, the following may occur. [/FONT][/FONT]l [FONT=Arial,Arial][FONT=Arial,Arial]Immediately after AUTO is pressed, the fan may stop for a while until warm or cool air is ready to flow. [/FONT][/FONT]l [FONT=Arial,Arial][FONT=Arial,Arial]Cool air may flow to the area around the upper body when the heater is on. [/FONT][/FONT]l A/C [FONT=Arial,Arial][FONT=Arial,Arial]does not operate even if it pushes AUTO.
[/FONT][/FONT]

 

I don't think that's a problem. You can always turn AC on, but there are times when you can take advantage of automatic control of the fan for ventilation (or temperature control when it's cold) and not run the AC at all if it's cool enough to not need it.

I have run mine on auto with AC off and think it's an intentional operating mode.

 

If you have the AC button pushed (green light AC on) and turn the climate control off the AC light will still be on when you turn the climate control back to Auto. Conversely if you have the AC off and turn the climate control off the AC will not come on when you push Auto. It remembers what you had selected when you turned it off even if you turn the car off.

As jim256 said just because the green AC light is on does not mean the air conditioner is running, when you are in Auto it uses heat and AC to keep the temperature where you have it set.

 

I tried mine on the way home and one thing I noticed is that if you are in Auto and switch the AC off, the vent changes from recirculate to external. When switched back to AC it switches back to recirculate.

 

Yes and I notice that if in MODE you select feet and windshield that the AC will come on without pushing the AC button and the light will stay out , but cool air will blow.

 

This, of course, depends on the temperature you set, outside air temp, and the other signals used by the A/C system. I've seen it go from Recirc to External and vice versa with the A/C light on.

 

Well that explaines something...My AC almost never jumps out or recirc mode... unless I force it too. In my other vehicles the auto aC was always quick to go from recirc to outside air...

 

um, how is that a problem? If there is no air conditioning turned on, how is the car supposed to be cooled? the only air that will blow in is the air from outside, so whatever temperature it is outside, you'll get. If its 120 degrees outside, then yes, it will get hot inside your car if you dont turn on the a/c.

this is simple logic? If you turn the a/c off, of course its going to get hot.

 

Sorry, i don't understand the logic. If I have a the AUTO selected and temp set to 20C it means, IMHO, I want 20C inside the car and doesn't matter that ambient temperature is 30C, so A/C should be switched on. But the car, instead of switching A/C on, just increases the speed of blower to max, which could not lead to the inside temperature decrease result becasue it is blowing the 30C air.

 

Reset it. Turn it off, and then press Auto. It should turn the A/C on automatically. And if it doesn't, just press the a/c button. Big deal.

I mean really. Nobody has ever used climate control before? Dont like the fan speed? reduce it. The Automatic function is designed to get to the temperature you set as quickly as possible. If you deselect the a/c, then it cant cool and it will just blow hot air.