AC auto mode fan power logic?

[drummerboy7816]

I'm not sure if my AC is not working correctly or maybe it's just the weird logic of how the auto mode works, but I've been noticing that when my car is really hot, like 85+, and my auto temp is set to 73, the AC fan on auto mode is like 4-5, with only the front air direction selected, thus taking forever for cool down. In my mind, the AC should blast the fan till it gets close to 73 then calm down, but that's not what's happening for me.

Is this normal or does something seem off?

I don't remembering having this issue in the past, so maybe it's a firmware issue? 2015 85D version 2019.24.4.

 

[JasJ]

My car blasts at speed 10 until its close to desired temp then uses fan speed 5. Example drive from last night (courtesy of Teslafi) on my MS.

(First row is getting into the car... many rows of data after with fan speed of 5 - first 3.5 minutes of driving below)

 

[drummerboy7816]

Thanks Jas. I'm starting to think that my internal temp gauge could be off some how by a few degrees. If I turned auto to 65 then it would start blasting more and get it to what I think is closer to 73ish.

 

[hpartsch]

Thanks Jas. I'm starting to think that my internal temp gauge could be off some how by a few degrees. If I turned auto to 65 then it would start blasting more and get it to what I think is closer to 73ish.

Any update on this issue? Mine was doing the same. Not sure if it was related to my MCU failure though.

 

[drummerboy7816]

Any update on this issue? Mine was doing the same. Not sure if it was related to my MCU failure though.

As it's not as hot anymore the problem seems to have fixed itself. I think for some reason the fan has a max fan setting or something so when it's on auto.. so example would be if it's like 95+ outside, car temp is 105, I set it to 73, it would only turn the fan say at 5, and with that setting the car may never keep up wit the outside temp and best it gets to is 85 or something. Now that it's 85-ish outside, the same auto fan speed at 5 would get it to 73. Don't know if that makes any technical sense haha.. but that's what I feel is going on.