F_R

My 2010 RX350 was sitting in the garage last night, engine off for an hour or more, and I heard a small elect motor sound running under the car? It was a humming sound, a bit like water running through a pipe or a small elec motor running. I crawled under the car from the rear and could tell for sure it was coming from the car and just as I got closer it stopped. Anyone heard similar sound?