[Stockholm 300C]

I heard it today in my 07. I turned the engine off, then the lights, pulled the key, and there it was. As if someone is quietly tapping a finger somewhere inside the dash. I thought it might be the accessory timer, so I quickly opened and closed the door. Then there was a quiet electric motor sound for a second, then quiet. Beats me what it is, but I think it has to do with whatever keeps power to accessories until the door is opened.