Aircon won’t stay on?

[Mrklaw]

Noticed this with the cold weather and did some fiddling in the menus

The AC doesn’t seem to stay on in ‘auto’ mode - and as a result you can very easily get into a defrosted car but with the inside misted up from condensation, and then have to hit the AC button and wait another 5 minutes for it to clear. Seems like if you have it set to auto, the AC is often disabled when its just heating?

On my previous cars, ‘auto’ was just the temperature/fan speed setting, and the AC part was always on/off based on whether I pushed that button. I tended to leave it on to dehumidify and avoid misting up the inside. On tesla if you press Auto it seems to decide itself (badly) whether it needs the AC on, and I’m guessing if its cold it doesn’t think it needs it even when it clearly needs dehumidifying. If I force the AC on, it switches to ‘manual’ mode and then that leaves the fans at whatever speed they were on (when you really want them variable based on current temperature), so thats not ideal either

Any way to get it to behave more ‘normally’? I guess its trying to save energy but shouldn’t that be my choice? and is there any way to confirm/change from the app if the AC is enabled when defrosting in the morning to avoid me having to take a microfibre cloth with me to my new car to clean it up, or sit and wait 5 minutes which defeats the point really.

 

[spooksman]

Did you defrost the car by turning on climate from the app?

I've noticed that if you do that, and turn it off from the app when the cabin gets to the desired temperature, then all the aircon/HVAC is fully off, and the car chills down really quickly - you then need to turn it on manually again after entering the cabin.

 

[Jason71]

In cold weather the AC can get iced up meaning that the AC does not actually function properly whether its on or off. The expansion part of the system gets cold and water condenses on it from the air then drips off. this is why you see the water under the car. In cold weather this water can freeze and form a block of ice which then prevents expansion of the gas because there is not enough air flow or heat available to allow for the phase transition. I am not an expert but I think this can in, extreme cases actually damage the system since the incoming gas to the compressor can be under too high a pressure. It certainly stops the system functioning properly. As a result systems have a pressure sensor and will shut off if icing occurs. This is true for all systems but no doubt varies from car to car. So it may well be that the car is shutting off the AC for this reason

 

[Mrklaw]

Aside from preconditioning - i checked in the car after finding the inside windscreen misted up (actually quite wet)

So from the car controls (car was warm) - I had it on auto but noticed the AC button wasn’t ‘lit’. I pressed it to dehumidify and demist the inside and noticed it then turned off ‘auto’ into manual

 

[ShadowSix]

I've also had this recently, although I could manually turn on AC, but it seemed to refuse to come on in auto mode resulting in all windows misting up and having to pull over to sort it out. I then noticed in tiny tiny writing on the depiction of the screen within the HVAC screen the message "Climate keeper unavailable due to system fault".

I don't know what part of the system was at fault. I tried a two button reset but the problem persisted. It also (perhaps unsurprisingly) threw a warning when trying to precondition from the app.

It fixed itself overnight.

 

[MrBadger]

I've also had this recently, although I could manually turn on AC, but it seemed to refuse to come on in auto mode resulting in all windows misting up and having to pull over to sort it out. I then noticed in tiny tiny writing on the depiction of the screen within the HVAC screen the message "Climate keeper unavailable due to system fault".

I don't know what part of the system was at fault. I tried a two button reset but the problem persisted. It also (perhaps unsurprisingly) threw a warning when trying to precondition from the app.

It fixed itself overnight.

See this post

We had that a few times last year - as it is not an entirely obvious error message (what was more obvious was weird cabin temperatures) but it started this time last year then settled down. Next noticed in summer with ineffective cabin cooling on a very hot day (a couple of days earlier I had questioned weird HVAC performance so probably then too) when I just happened to be sitting in car waiting for the driver to get their ice cream so had a bit of time to delve. Not helped by the error being so subtle and only visible when parked.

Reported to Tesla and fixed by SC with (iirc) a new temperature and humidity sensor.

 

[ShadowSix]

See this post

That's useful info thank you. Over the summer I reported inconsistent cabin temperature control, but they ran their tests at the service centre and reported no fault found. Although this issue from the other day appears to have cleared, I'm going to leave it on the service booking I've got coming up (for a separate problem) and we'll see what they say this time.

 

[Irata]

I've also had this recently, although I could manually turn on AC, but it seemed to refuse to come on in auto mode resulting in all windows misting up and having to pull over to sort it out. I then noticed in tiny tiny writing on the depiction of the screen within the HVAC screen the message "Climate keeper unavailable due to system fault".

I don't know what part of the system was at fault. I tried a two button reset but the problem persisted. It also (perhaps unsurprisingly) threw a warning when trying to precondition from the app.

It fixed itself overnight.

Exactly the same happened to me two days ago.

In my case it was just letting the car sleep and wake that fixed it, so the same really.

I tried a reboot and a full power off, they didn't work.

No issue since, but also I'd never seen this before.

Also..I guess the car uses the humidity sensor to determine if AC is required on Auto. But given quite a few have started to see these issues at the same time, maybe it is a software fault

If it happens again, I'll take a photo of the screen and report it.