Whistle from HVAC while in footwell-only mode

[Esquire]

Just curious — does anyone else hear a pump-like sound when the HVAC is on? With the stereo down/off and the truck parked or stopped, I hear a whir that runs for about 10–15 seconds, winds down, then starts again. Sounds like some kind of pump. I assume it’s normal, but wanted to see if others notice the same thing.

Yes. Once in a while I hear that as well. The HVAC system seems to make a number of unique sounds. At least that's what the guy down at the gas station told me....