HVAC fanspeed on highway

[victimofareload]

Greetings all. I did a bit of searching but didn't find any other topics on this.

I first noticed this on my 2021 Lariat powerboot. But after having a 2021 XLT rental, I noticed it does the same thing.

If the AC is running. And you get on the highway (I notice it on i95 here in central florida). I'll have the HVAC fan speed somewhere between 1 and 4. After awhile I'll feel the wind coming towards me suddenly increase (Like double). Without changing the fan speed. It doesn't get warmer or colder. It's like the fan speed is suddenly increasing 2-3 clicks. It'll go back down a few minutes later. Only to do it again 10-20 minutes later. Doesn't seem to happen unless I'm on the highway.

The last time it did it (In the XLT). I turned the fan speed down one click and then back up and it made no difference. It continued to blow much harder then click 3 normally does.

I'm confident it's not just my truck because the XLT rental did it too. But I'm curious if anyone knows why.

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[parkerdog]

Recirculation cycling maybe?

 

[victimofareload]

Recirculation cycling maybe?

Perhaps! I'll have to try turning recirc off next time. I normally always have it on as I start at "max ac" which forces it on. Then back the fan speed down as the truck cools off.

 

[Oxford_Powerboost]

I haven’t experienced that, but I use auto exclusively. I’ve always known the air to blow harder on the highway when not on recirc, simple as air being forced in by going down the highway at speed. But shouldn’t oscillate at the same vehicle speed and fan speed I wouldn’t think…do you have the A/C on during this? My previous car would occasionally give me a note that auto air quality system was active, automatically blowing A/C harder than normal when high humidity was detected if I was manually controlling the HVAC. Wonder if the truck does something similar when not in auto mode

 

[RedTXV]

Known issue. And yes, it’s the recirc turning off and is designed this way. Quite a few threads on this.

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