What is this noise?

Truck has been parked for about five hours. Just walked outside and as I walked by the truck I heard this noise coming from somewhere under the bed. Took it for a ride. When I got back and parked the noise had stopped. Checked again 20 minutes later and still not making the noise. Sounds like a mini air compressor... Anything?
On the video it sounds a little louder than it actually is.
https://drive.google.com/file/d/1NFGitZ4A0jscNnZCywY6UcEOWeSGH3JI/view?usp=drivesdk

 

Evap system. Normal.

 

Gotcha. Thanks

 

It's the craziest thing! I can't tell you how many times I've been turning lights off going to bed or in the laundry room and hear something in the garage and it's that stupid pump! Thing runs all the time, but you leave the truck door open for 10 minutes to vacuum and the truck is in panic mode with CHECK ELECTRICAL SYSTEM!

 

Your owner's manual makes reference to this noise as well, if you want to know a little more about it.

Happy Friday!

 

https://www.youtube.com/watch?v=_frXYiZ-cAo