Pretty sure it was the pump, it was a very faint noise which I never heard before, only audible because the car was in a small garage.
Can the fans run with the engine off/car closed?
I have heard it too, inside the garaje. The sound of it is a soft hum when turning off the car on hot days and with a hot engine.
No one can clarify in detail, on what parameter is the EMC based to turn it on and off? thanks
Electric Coolant Fans Continue to Run after Ignition is Switched OFF
I am wondering if that hum you are hearing is the TB, I know that if I turn the key on but do not start the engine you get a humming noise from the TB for a little time, I also hear this noise when turning off the key back off or the engine off.
As for when the pump runs?? Vw just states hot engine in the SSP and thats it. I guess you could hook up a test led light together with the coolant pump plug and see at what conditions cause it to run for more than a few sec.