Moldy smell when fans turn on

Is it anywhere in the manual or a EU version?

I had to check again and p.359 of the Owner's Manual says:
"If the “A/C” switch is not pressed, the system will blow ambient temperature air or heated air."

Which is what I would normally expect out of a car but it seems wrong from my experience. If I get in my car with outside temp of 35c and just turn on the ventilation speed with a temp of 25c in manual mode, the A/C button light will be off but it will be blowing cold air. In my case, it feels like 'light off' could mean it's off, it's on auto or it's on because that's how it behaves.

 

What's the car?

 

Well, if the setting is "auto", then obviously it could be currently running or not. If you're feeling cold air, it's presumably because it's in auto mode and currently running.

I'm not sure what sequence of buttons you're pressing, but presumably the AC could have been left in "auto" when it the climate control turned off, and it would presumably just go back into auto as you select a manual fan speed.

It's the same as the settings for speed and air direction - it will remain in auto until you set it otherwise, and then once you've set it otherwise, it goes back to auto when you press the auto button.

If you're feeling cold air, just press the AC button until the light is off. It's not rocket science!

There is a settings screen in the multimedia display (Vehicle > Climate > Front) that does show the OFF/ON/AUTO tristate for A/C properly. Don't recall if the touchscreen button lets you select A/C AUTO, but it does show it, unlike the LED on the physical button. You can watch that to figure out what the physical buttons are doing.

 

One would think so!

It's not in auto mode when I do it. Here's a sequence: I start the car, I select temp I want, fan speed and vent mode. The AC light is off.

Cold air blows out with a 10c differential easy between inside the cabin vs outside air.

I press the AC switch, light comes on, still blows cold air.

I press the AC switch again, AC light is off, still blows cold air.

Now I never checked the multimedia screen as I usually just project the phone automatically. I'll give it a shot and see if it tells me whether AC is on or not but with a 10c differential, there's no way I should be getting cold air. Maybe it's stuck in auto mode or my AC button isn't responsive.

Listen, I feel crazy because this is the one part of this car that makes no sense to me and I haven't figured out yet. It's routinely 35-40 celcius here so AC is on most of the time but occasionally temps drop and I'd like to get ambient air from outside through the vents and I haven't managed so far other than the way I've mentioned earlier.

 

Is it a plug-in? Could be that the A/C compressor is running for the benefit of the battery (would make sense if outside temperature is >35C), and you're getting some chill from that. I don't recall how much effort it makes to avoid any chill effect reaching the cabin when cooling the battery.

(Afaik, you do not have any ability to stop it cooling the battery when driving - if the battery needs cooling, your climate control choices won't stop the compressor running).

 

I forgot to answer Mendel but it is a 5th gen Prime so yeah. I thought the Primes had a liquid-cooled battery so it wouldn't need the A/C on the new gen and the HEV was still air cooled. For example, I have no air vents in the back under the seats whereas the HEV does if I'm not mistaken on 2023+.

I'll test it out from the multimedia screen and report back!

 

If I want uncooled outside air, it's three button presses for me(assuming I start in Auto mode).

1. Press the "Outside Air" button (it will light up)
2. Press the "A/C" button (it will light up)
3. Press the "A/C" button again (the light will go out)

The first A/C press switches the A/C system from auto mode into manual mode and sets it to on. The second button press keeps it in manual mode and turns the system off. This mode will continue until the Auto button is pressed again. I think the setting is retained through shutting the car down and restarting, but I'm not absolutely certain of that.

If you always want full control of when the A/C is running or not, go into your climate settings on the infotainment system and disable the setting "A/C on Auto". That will take control of the A/C away from the car and give it to you. Then the A/C system will only run when the light is on. (This is basically the old way from previous Prius gens.)

 

I was also wondering if that was the case(it being a Prime and the A/C running for the sake of the battery). But I have to assume there's a valve shutting off refrigerant to the A/C box coil when the climate control doesn't ask for it. I wonder how long it was still blowing cold air and how cold it really was? If it was just cool air and for only a few minutes, then it was probably just residual cold in the A/C box. But if it was longer than just a few minutes, I'd be a little confused.

 

I keep life simple, I just put mine in auto, set it to 21.5C, and never touch it. Still get almost 85-90km of EV range in summer with that and my driving habits.

If the moldy AC smell starts in the future, I'll just run a can of cleaner through the drains. So far after 8 months haven't had to do that yet.

 

Went to check in NCF, and yes, there is.

 

Alright so update! I've finally learned how the AC works! heh

Like Hammersmith said, from auto, two presses shuts off the AC but there's some residual cold air for a while. I haven't checked how long but it was a couple minutes so far, at least. I'll try it next time I go for a longer distance.

Now the weird part is when I shut off the car and start it the next time, sometimes the AC is in manual mode and others it's back in auto. I'm wondering if it might have something to do with the two keys and it saving different settings for the AC.

The climate screen in the setting for the AC is really helpful to see it's current state since you can't really rely on the led on either the AC or AUTO one.

Now, does anyone know where the drain tube and intake is for the AC unit? Usually AC is under the car passenger side and intake vent is at the bottom of the windshield but I haven't seen anything confirmed for this car. Dealer wants $200+ for an AC clean and mine is starting to smell on startup. Mine started around the 12-13 months mark and has gotten worse since. I don't think I've seen anyone report cleaning out their ACs yet!

All I found online so far are these old TSBs:
https://static.nhtsa.gov/odi/tsbs/2014/SB-10060721-2280.pdf
https://static.nhtsa.gov/odi/tsbs/2020/MC-10172826-9999.pdf