Change auto AC's default fan speed?

i find this annoying as well. hopefully there is a solution

 

i never use auto, just for that reason. would be great to have it default to 2 or 3 bars.

 

Try raising the target temperature a degree or two. Or three. 'Till the fan speed falls back. As the car cools (and it will, even with moderately high temp set) drop the target temp incrementally, not so much that the fan races, until you reach some kind of balance.

I find 24C good, what's that in Fahrenheit, 72?

 

Try Auto in ECO mode.

 

Raise the target temp to 76~78F. Yeah, I know makes no sense, but humour me. And trust me: it'll still be cooling. Raise target temp enough and the fan speed will go down. Play with the target temp until it does. Then as the climate stabilizes start bumping the target temp down.

 

And I think you are absolutely totally wrong in saying that.
It may not change at exactly the points you think it should but it will change.

And I have never noticed that "problem" with my C......or any other car for that matter.
I sometimes think the fan should be running FASTER, not slower.......and I can get it to do that with a slight adjustment of the target temp.

 

What are you using to read interior temp?

 

JD posted a good question. The temp on the display is the ambient outside temp, not the interior temp. So, if it read 73, the interior temp was probably a few to several degrees higher resulting in a high fan speed with the auto set to 72. I've had no problems with the auto setting. It comes on high when the temp diff is great and low when it isn't. I assume you don't have the defroster on, that always comes on high, at least in my experience the few times I've had to use it.

 

Anyone who knows anything about air conditioning, knows that the fan must circulate air through the evaporator at a certain CFM rate or the evaporator may frost over.

So, that is why the fan is programmed automatically for a higher speed.

 

but in manual, it allows you low fan speed.

 

Right. Even if you're not confusing interior with exterior temperature, and are using an accurate thermometer, it makes a big difference where you're measuring the interior temperature, because of solar radiiation in the daytime.

 

can't you read the interior with an obd II?

 

Correct... The compressor just cycles off more often, and it will take a lot longer for the interior to cool down.

You wouldn't want a block of ice in the evaporator. It's basic air conditioning; NO need to explain it in complicated thermodynamics.

 

gotcha. i kick mine on manually, start with a fan speed that suits my cooling patience, then slowly bring it down.

 

Mine also did it. I used the downloaded app "Carista" to configure the sensitivity temperature so the fan speed is lower.

 

Minor detail: The Prius uses a variable-speed compressor, it's not cycling on and off.

Also, I've tested it by manually setting the temperature to the minimum and the fan speed to the lowest, and watching the compressor power on a ScanGauge; the compressor stays at full power, even though very little air is moving. Maybe there's something else that prevents it from icing up, but it doesn't kick in right away.

 

I'd say live with it.

If the outside temp is COLDER but the sun is out, the temperature in the AC unit may be high enough to make it think it needs the blower on high speed. As soon as the temperature drops in the AC vents, it will adjust automatically. This is all perfectly normal.