T4 humming noise

[Black Angus]

When I shut down the T4 after driving either long or short distances, I hear a humming(buzzing?) noise, which can continue for up to a minute. obviously, I'm not referring to the radiator fan. Said noise is much quieter than that, and sounds electronic? in nature. I'm just curious. Any ideas?

[kenney]

I think you have an auxilary heater (Eberspeche) and this is after burning,a cooling down process after you shut down the engine,if you have a look in front of the left front wheel you will be able to see the exhaust pipe ?????????????????????????