Mmr1

When I run the Ac on auto, even if car just comes out of a 70 degree garage from all night, and is fine, on Auto Ac the fan runs fast and noisy, equal to about nearly 4 if you were comparing it to running the fan manually . Actually near 4.5 in sound volume. Shouldn't it slow down to 1 -2 when it's normalized . So it's nice and quiet. To me the fan speed on auto is always anoyingly loud.

bop11

There is a small circular screen on the dash near the steering wheel that is an inlet for the interior temperature sensor. If this is plugged with lint or other material, the car will not sense the correct temperature. As the interior of the car reaches the set temperature the fan should slow down if the heat load ( sun through the windows, outside air temp etc. ) goes down. On a hot sunny day, the fan will stay high to keep the car cool. Cooling the interior of an SUV takes a lot longer than a sedan due to volume and windows. With temps in the high 80's lately, after sitting in a parking lot until lunch it takes mine 10-15 minutes to get cool enough for the fan to go down.
Unfortunately the car seems to blow very cold air at different speeds for cooling rather than mixing warm and cold air to give the proper temperature out of the vents as older cars use to do. So my hands freeze until the fan goes down. I guess this is to try to cool the car as fast as possible.

shotgun_banjo

One of the things I do is set the air vents to the windshield and hit the Auto button. This will quiet down the fans and will do its job and next thing I will know it is almost silent when the temperature gets to what you want it to be. bop11 is correct that sometimes it takes time to cool down the car specially when it is really hot.

Mmr1

I don't think I'm explaining it right, even in winter, at 40-50-60f, the temp changes out of the vents, desired temp is fine, but fan speed won't go below 4-5, so it's noisy . I've been forced to run manual and adjust fan speed because above 3 gets bothersome sometimes. So I don't use Auto. I rarely need over 3 on fan speed, but on auto, it just always runs faster. I think it could run at 1-2 speed, but won't . Ok thanks

bop11

To answer your first question, Yes, it should slow down to a speed that is inaudible. At least mine does.