Buzzing / humming from super charger while truck is off

I've come to seek some guidance on this board. I recently bought a '13 Taco with supercharger. I get home at about 9pm. I go outside at about 0230, and hear a buzzing and humming in my driveway. I basically narrow it down to the truck and the supercharger. What is going on?? I turned the truck on to kind of "reset" it, it turned off, and then it sounded like all was off. What is the deal?? As I'm using it today I'll keep an eye on it and the air/fuel ratio just to see if something is jacked. I feel like that should not be happening.

Appreciate all and any help.

If anyone is wondering why I'm up at 0230, got a new dog and was giving her pee breaks..... :/

 

Totaly normal. Intercooler cooling circuit pump. I dont remember exactly but the pump is feed trough a circuit that is periodicly activated when the ECU perfom some test. Someone can confirm but i think it's related to some leak test on fuel tank.

 

Wow dude, that makes me feel so much better. I just bought this truck, had it transported from another state to Florida, so following up with problems is not quite easy.

I'll still wait to see what others think as well, but definitely appreciate the input.