I have a '23 Luxury model that I've had for about 6 months with around 5k miles now.

When I have the A/C coming from the from vents, I can feel and hear the fan speed decrease significantly depending on vehicle speed.

From a dead stop to about 18mph, the fan speed is what you'd expect based on the fan setting. But once the speedo tops about 18mph, the fan speed goes down significantly (despite the actual fan speed setting not changing). Then slowing down for a stop sign, red light, etc., I can feel and hear the fan speed pick back up again around 18-20mph down to 0mph.

At first I thought it was some annoying 'auto' setting. But the physical Auto button is not lit up, nor does the 12.3" screen say the word 'auto' under the fan setting. Climate concierge is also not on. I've dug around the menu screens in both the 12.3" display and the multi-info display and don't see anything that would indicate the A/C isn't on a full manual setting.

I've tried toggling Auto off and on to see if that 'resets' it (it doesn't). I'm always driving in normal mode. I've tried sport mode as well as having the shifter in sport mode but neither has an effect on the problem.

No warning lights ever come on, and there's no other weird behavior (such as typical weak battery or alternator behavior). I'm wondering if this fluctuating fan speed behavior is by design, like some horrible forced efficiency 'feature', or if it's a flaw that the dealership service needs to fix, or did I somehow missed something in a menu setting?​​

 

Click on the Vehicle Icon on the 12.3" display. Choose Climate, then choose Options. Make sure Eco mode is turned off there.

 

That's turned off (was hoping that was it though).

 

Then you'll want to have the dealer look at it. That's not normal, mine does not do that. Since you're at 5k it's time to go in for your free tire rotation anyhow.