I have a 1993 Honda Accord LX, when I push the air recirculate button, it only makes a buzzinig sound. I've looked underneath the dash on the passenger side and have been able to identify the general area of the problem but can't identify parts or problem. The blower motor and the door in front of it are operational, however directly across from it is another fan of some sort with a door, the door is not moving and the buzzing is coming from that unit. What is this unit, how is it attached to the recirculate and what could possibly cause it to be stuck or cause to be buzzing? local honda dealer said they had no clue and it could cost upwards of 1000 to take the dash off and figure it out. thanks for your help!