weird electric pump noises and it sounds like coolant circulating long after I have turned it off

I'm sure this is normal because I have heard the truck do this since I have bought it but just curious what it is. Long after I turn the truck off I have went out to my garage only to hear my truck sound like it has a pump or something running then it will turn off. It's like a humming sound kind of like that of a compressor for an air ride system but I do not have an air ride. I do how ever have a sport with the tow package and trans cooler. I'm writing this post to basically find out if anyone else has noticed their truck do this and what is the culprit? I'm not worried about it unless I need to be because I know newer trucks and cars have systems that can activate without the key in the ignition to keep the vehicle primed and/or running right. Any type of answer would be greatly appreciated. It is heard from underneath the truck on both sides so I can't really narrow it down because I have been to lazy to actually lay up under while it is doing it to pin point where it is coming from. Thanks for any input.

 

the trucks computer has been hacked and somebody is screwing with it, that or it is coming to life and will drive away on its' own

 

smog pump

 

The smog pump will run right after shutting the truck off. It's a prime pump on the fuel system. I swear sometimes mine will come on when my truck has sat for days. There is all kinds of threads about noises the trucks make

 

^^thanks I figured as much. Yea I have went out to my garage on a Sunday and my truck did not run on Saturday and the thing will kick on. At first I was worried but knew being a new vehicle there had to be some gadget that was the culprit. Thanks for the conformation!