Hey guys just recently purchased a 06 300c and this morning got in the car turned the heat only defrost to clear windshield let the car warm up started driving and switched it to the vents and no matter what I tried it would only pass thru the defrost vents. The green running lights on the hvac do not work but all other controls work properly so I got home shut the car off and now I hear a faint steady buzzing sound behind the radio and hvac unit with the car on or off what is this and how do I fix it.. thanks