[Harvey]

When the ACC is set to 'recirculate' there is a hissing from behind the facia.
My son recons it is a vaccuum leak; it does sound like one.
The question is; is the flap, or whatever shuts off the outside air, controlled by vacuum, or an electric motor or solenoid?

Harvey

 

[pete_turier]

The flap is controlled by a (very expensive) motor.
I wouldn't have thought that was the cause of the hissing. More likely the flap is not seating correctly and causing a rush of wind!!
Pete.

 

[Harvey]

Thanks Pete,
I found the info on the Townsend site as well. Should've looked there before asking.