AC light off when AC is on

I think this quirk was discussed in a thread back when the gen5 first came out.
It could be how all auto HVAC systems are these days.

 

If you have access you can customize this parameter so that when the car is in Auto mode the AC compressor defaults to off until you turn it on with the button.

I think I might do it so I can keep the fan on on a hot day when I leave the car parked without having to consume as much power with the AC compressor running. I have yet to try it but am pretty sure that is how it works.

 

Notice that when you put it into AUTO, the fan speed, air direction and fresh air/recirculate indicators also go off, not just the AC light.

Anything being automatically controlled shows no indicator. If you touch that setting it is manually overridden and the indicator comes back until you reselect AUTO.

The AC button light cause the most confusion because there's no visual difference between auto and off. But you can find this somewhere on the climate screen menu - an on/off/auto three-way indication for the AC.

 

I believe 'ON' there means pressing AUTO switches the AC to auto, and 'OFF' means it leaves it alone, so leaving your manual on or off state.

 

I am not quite sure what you are saying. You are saying that auto climate button on and the ac button off does not run the ac compressor?

Let me add a little of my anecdotal experience. From running my climate control in room mode and using the Auto setting the while the car charger is attached to a power meter I have observed that in the Auto mode the AC compressor runs quite a bit if not all the time a draws close to 1 kW of power. I can be heard as well.

I will have to check that screen again. Not sure how it different from the setting in Techstream. Might be that the climate setting on the screen changes how the indicator light behaves while setting in Techstream changes the behavior of the AC compressor. Pretty sure I remember there being a little explanation in Techstream too that confirmed my experience that default from the factory the AC compressor is set to run most of the time when the climate auto setting is selected.

 

I'm saying the AC control has three states. On, off and auto. Pressing the physical AC button switches it between on and off.

Pressing the physical AUTO button will set AC to auto if the Techstream control to link the AUTO button is ON, as it is by default. (And isn't that also exposed as a setting in the UI too?)

The light on the button is off if AC is in auto.

If you press the AC button once or twice so the light is off, then that will set it to off and stop the automatic climate control from using the compressor for cooling. Although it will use the compressor for heating regardless in the PHEV.

And yes, auto does seem to run it a lot of the time. But it's still a distinct state in the control system. I think that's different from the G2 which seemed to only have off and auto. I think what's been added is the ability to force AC to run with the added 'on' state. Not super useful, while complicating the UI.

The setting in the UI I was referring to in my previous post was the 3-way indicator for the current AC state, expanding on the 2-way indicator of the button light. Not the 'does the AUTO button select auto AC' option.

 

Looking at the manual, the AUTO light also turns off when fan speed, for instance, is changed, but other auto functions still operate. Pressing AUTO again puts it back into full AUTO, controlling fan speed, etc.

I never use AUTO. I have default set to OFF in the multimedia screen, below. I set the temp and fan speed (and A/C) manually. And of course, FAN OFF for max mileage, lol.

 

Then, there are settings for keys. Not sure if I have that, lol.,
edit: Maybe if summer ever comes I will experiment.

 

That's because you have a Prime; it's battery pack is cooled by freon from your AC compressor.......

On a regular Prius, where the pack is under the rear passenger seat; the pack is simply air cooled and you sometimes get the question, "do you want to enable the AC to cool the pack?"

You guys need to be clear in car configuration and default options your talking about, because this can get messy really quickly.

Just my 2 cents....

 

I think I might be getting it:
With this selected OFF, A/C compressor doesn't automatically come on. So Auto is basically heat only unless A/C button is pressed? Of course, you Prime people are different....

You still have to hit AUTO I guess.

 

Let me clarify after reading the repair manual. In addition it is important to note that this is in the PHEV version of the repair manual.

You can customize it either in Techstream or in My Settings using the MID and going to -> Settings ->Vehicle Customize -> Climate.

Here is how it appears in a table from the repair manual.



And here is how the customize in my settings appears in the repair manual.


So my understanding of what this setting does is change how the A/C compressor behaves when the climate system is ON and in AUTO mode. The default is to run the A/C compressor in AUTO mode all the time. By changing this setting the A/C button will need to be pressed to run the A/C compressor.

I don't think that is correct. I think the way the car comes from the factory and what this particular setting changes is what happens in AUTO climate mode. AUTO climate mode default from the factory runs the A/C compressor all the time. By changing this setting it turns the A/C compressor OFF in AUTO mode. I am than guessing that you can manually control the A/C compressor in Auto mode by pressing the A/C button.

I haven't tried this yet so that previous sentence may not be correct. From my experience when you press the A/C button in Auto mode you cancel the AUTO mode. This still might be the case when the setting is changed so that A/C compressor runs only in with manual control and not at all in AUTO mode or more as needed automatically.

You are talking about on the media center display? If so, what are you saying this setting changes?

 

Just because the AUTO light turns off, doesn't mean it still isn't doing its auto thing, just without the thing you changed. In my example it was fan speed, in yours, it's A/C. I think. To get AUTO back in total control, you have to hit AUTO again, and then AUTO light will come on. To turn AUTO off, hit the FAN OFF button.

And, like I said, My Settings is a whole other ball of wax.

I agree, but I'm no genius.

 

I run my gen4 Prime HVAC system in manual mode 98% of the time and I've noticed that the AC compressor will turn-on to generate heat, if the cabin temperature is below set-point. AC lamp DOES NOT turn-on. You pop the hood, the compressor and cooling fan are ON - car is in heat-pump mode. My understanding is that this is a Prime ONLY function; standard Prius doesn't have a heat-pump function.
The only time I switch it to auto mode is during long road trips in very hot weather. I get tired of toggling the system ON-OFF. I usually have to crank the cabin temperature way up to keep from freezing and the fan level to a low drone. Then the next morning, I have to reset everything back again.....

 

And I'm glad of it.
I made an impulse buy of a heat pump combo washer/dryer last year. What was I thinking?

But seriously, are you sure it's on to heat the cabin? If you turn off HVAC does it shut down?

 

Yep; outside temp. is around mid to low 50's cabin temp it set to 68 in manual mode with low fan speed, about 1-2 bars. Mild heat out of the vents. Adjust cabin temp. to Lo, compressor and cooling fans stops, interior HVAC fan still moving air. I get regular furnace heat when the ICE kicks on; and I'm assuming the compressor will kick off too. Didn't stop in the middle of the highway to check.

 

got it. I think I mis-read earlier.

 

Yes, in vehicle> climate - the main control screen, not the detailed settings.

It changes the AC setting - the same thing as the physical AC button. Directly, not some extra behaviour option like your setting menu thing.

I'm directing you to it because it directly shows the 3 states of the AC control - on, off and auto. The fact you haven't seen this and think it's a 2-way control is confusing you. Keeping that screen up while you mess with the buttons should clarify AC and AUTO button behaviour.