Electric motor running, truck off

Came out to the 4Runner this morning and heard an electric motor running, somewhere underneath in the back, in the spare well. Truck was off, the accessories didn't seem to be on. Starting the truck went fine, shut it off and the motor stopped. Searching the forums here didn't produce any ideas, but I swear I saw something somewhere at some point. Does anyone know what that was?

Thanks!

 

Evap test. Totally normal.

 

Cool. Thank you!

 

Normal and mentioned in the owner’s manual.

 

Same thing happened to me

https://www.4runners.com/threads/electric-motor-sound-in-back-of-vehicle-while-engine-is-off.35527/

 

100% normal.

 

The first time I heard this sound it was in the middle of the night when I was in the boonies sleeping in my Tundra, and it woke me up. It was a bit worrisome since I didn't know what it was, and I waited for the truck to go up in flames or something