Vents sometimes blow a bit harder with AC? (1 Viewer)

[shtbrwn86]

Hopefully someone can just verify if this is normal. I didn't really know how to search for it and didn't find anything similar when I did search...

1999 LX470 248k miles

Driving on the freeway on a hot day with AC on, I notice the air coming from the vents will sometimes blow harder/more forceful, then return back to normal, even though the fan speed isn't changing on the display. Is this normal? Seems to happen whether it's in AUTO or MANUAL.

I also know when it is in AUTO, I see the fan speed indicator fluctuate to control temp (like when set to hot first thing in the morning.)

 

[ramangain]

Normal

 

[shtbrwn86]

Normal

Great. Thanks! Do you know why it does this? Just curious.

 

[I Lean]

It's probably switching back and forth from "fresh" air to "recirculate". I think mine behaves that way, anyway.

 

[white_lx]

Great. Thanks! Do you know why it does this? Just curious.

There are some algorithms in the A/C amplifier that take sunlight into account to determine how the occupants perceive the temperature in the vehicle and adjust for that. For example it will feel warmer driving into the sun. To compensate for that, the air flow will be increased. In their marketing they refer to this as a 'neural network'. 1990's AI.