Intermittent sound from underneath truck

[Tango21]

I have a 2019 GMC Sierra crew cab.  I’ve had it for just over a month.  After sitting for a long period (say, overnight) when you open any door, a squelch type sound emits from under the vehicle.  Lasts for a few seconds then quits.  Won’t occur again until the truck has sat for awhile.  Anyone else experience the same sound, know what it is and especially a way to turn it off?

[tbare54]

Fuel pump priming!


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