I have a 2007 roadster with 13K miles, and I noticed recently when I start the car (turn key to on) position I hear a "whining/humming"' noise and it sounds like it is coming behind the vents over the radio. My concern is that it recently is louder than before. It happens immediately when I turn key to "ON" position. Note: fan and a/c is set to off. I thought it could be the cold weather in Boston. Any help would be appreciated.