How does the automatic climate control work?

Assuming it's per regular Prius, if you hit AUTO, want to let it take control, then only select a target temperature. Doing that, the car will determine:

recirculated vs outside air
fan speed
mode (which vents to use)

If you expressly choose any of the 3 above settings, those will stay as you set them. What I'll often do: if the fan starts racing, is play with the target temperature, raise/lower and see what happens.

Also, sometimes the car's propensity to shut off at a red light can be affected by the temp you set. Especially when only partially warmed up, if the car's not shutting down at a red light, try dropping temp a degree or two, it sometimes will shut the car off.

At least with our Canadian 2010 hatchback, the AC button for the most part does what you ask, ie: if it's not pushed, and it's light is off, the AC won't be running. And vice-versa. The once exception I've sometimes noticed: if Mode is set to heat/defog, AC will sometimes come on, even though the AC button is not lit. This was determined monitoring AC compressor watts with a ScanGauge.

If the front defog button is pushed, then also yes: AC comes on. But in this case it's very obviously on, blasting, and the light on the AC button does come on.

 

Basically you run the system in "auto" or not. If you're not in "auto" mode, then you can control which vents the air comes out of, whether the A/C is on or not, and the temperature settings. The "recirc" button can turn recirculation on or off and I've found that you can control this whether you're in auto mode or not. I normally run in recirculation mode except in a few special circumstances such as cooling the car down when you get into it on a sunny day (because the inside air temperature is a lot higher than the outside temp, so I figure the A/C doesn't have to work as hard cooling the outside air for the first few dozen seconds while the inside temps come down).

The Prius C is the first car I've owned with automatic climate control and I've found that it works very well. You just push the "auto" button and select a temperature and the system does the rest. I'm pretty sure I've read somewhere that it not only senses the temperature, but also has humidity and sun load sensors which it factors into its actions. I occasionally prefer to adjust the temperature setting a bit when I go from sun to shade or vice versa, but that's about it.

I've found the front defog setting to be very effective and clears condensation off the windscreen very quickly. I've never had to leave it on for more than a half a minute or so, and that's in Vancouver Canada where it can get very cold, damp and wet. The rear defog uses the same kind of heating

 

Most of the time, and particularly at this time of the year, I switch the A/C to "Auto" and let the system do its thing. For the same reason I keep two cats rather than chase the mousies myself… …and for the same reason, if I ever needed a bark, I'd keep a dog! (Sheeeesh, some folks really like to complicate their lives!)

 

G'day,

Ahh, the inscrutable East. Maybe a Japanese immediately understands the Prius c climate system, or understands the manual on what does what, when, and what cancels what if a button is touched once 'Auto' is lit up. And what is still controlled by the car if the 'Auto' button self-cancels for some reason.

Over this just-past summer (the first 6 months of having the car), it was cooling only wanted so when hitting the 'Auto' button didn't seem to cool things down quickly enough (to the numerical temperature set), we'd hit the a/c button (green led comes on) and the Auto button went out and cooling was fairly immediate. Adjusting the fan speed also tended to turn off the 'Auto'.

Driving in constant 'Eco' mode probably had something to do with this peculiar-to-us behaviour of the system. I could try "Pwr" and see if it is even a little obvious about what is going on when in 'Auto', I guess?

Now we're getting into winter, it's heating wanted inside the car. So far, we just dial up a number well above what we'd like to feel (say, 27C for 23C when it's about 12C outside) and this seems to produce some effective heating over time without going too hot. The 'Auto' mode has not been used for heating, just the temperature dial. Fan speed and internal-external air are played with but what this would do if we were using the Auto mode, I don't know.

I'm curious to know where the system's temperature-controlling sensor is? I'm guessing just one for a small car like the 'c'.

I fear we're too old and too used to a simple manual (on-off) hot-cold system to 'enjoy' this 'Auto' feature of the car.

Demisting (the button for the front windscreen) is very good as it activates the air-con to blow low humidity air up the screen. But how using this during the 'Auto' mode affects what, I don't know.

Comparatively, the Prius 'c' climate control system so far makes understanding global warming and climate change a 'piece of cake'.

David S.

 

Since he hasn't been back on in 14 weeks to see his answers, I guess he didn't REALLY need to know.