Two questions about the air conditioner: 1. Why does the AC always turn on when you go from OFF to AUTO even if the AC was off prior to doing so? Any way to change that? 2. Is the AC an all or nothing thing? For example, if the AC is on in AUTO but I don't really need the car cooled that much, does it automatically turn it off even though it says on? Thanks!
If you have automatic climate control, adjust your set point temperature to a higher temperature. I changed my temperature from 72 degrees up to 75 degrees and the AC isn't on as much.
For the system to be fully automatic the compressor must run -- so the AC light goes on ... this is how ACC's normally work. Here in the northeast I need to have the compressor running most of the year -- otherwise the windows fog. The system used the Ac to dehumidify the air prior to heating it. The system modulates -- so it is not running flat out all the time and it will not run when the temps outside get down low. I never touch mine -- always in "auto" and AC light on .. the light is not an indication that the compressor is running at that moment.
So in other words it's definitely not like a home unit where you can actually damage it if it runs too long when it's cold outside? Also, have comparisons been done at lower temps (when you don't really need the AC on) to see if having the AC on affects FE a ton?
1. My AC does not turn on when I go from OFF to AUTO if it was off before. It only goes on if I press the button. 2. If the AC light is on the AC will only run if the cabin temp is higher than the ACC setpoint. Also the AC will run if you run defrost, whether the light is on or off, in order to dehumidify the air. At least that is way the Gen III's prior to 2012 worked.
Part of the confusion comes from terminology. Toyota uses "air conditioning" in the general sense: heating, cooling, and dehumidification. Most people in the U.S. use "air conditioning" only to mean cooling, even though not correct. We buy an air conditioner when we want to cool a room. It's a silly use of the term, but Americans have never been overly consistent with our use of English. So your Prius has an Air Conditioning system and also an air conditioner compressor. The compressor can be enabled and disabled explicitly. When enabled, the A/C compressor is only used as needed. It is electrically driven and fully modulated, so it provides only as much cooling as needed. It is perfectly okay to leave the A/C compressor enabled through the winter. The system will use it only when appropriate, and without damage. Tom
ACC systems are normally set up to keep the condenser below the dew point -- This removes the excess moisture from the air and keeps the cabin fresh and the windows fog free. You may not need to do this in very dry cooler climates. Many systems call this "ECON" Toyota uses "AC" -- the system is still maintaining the temp and the modulating the fan speed to maintain the temp .....but obviously can not cool the air.
I understood our cars have a thermo electric heat pump rather than an old fashion compressor. Which is it? Mike
The A/C light usually comes on when you hit the cabin scrubber button to keep the humidity down. When the scrubber mode times out and shuts off, the A/C light usually stays. As in all modes, if you don't want the compressor to run, hit the button to turn the light off.
