My A/C system has started an occasional whistle from the center air vents. It happens about a third of the time. It disappears when the A/C is off; actually it fades away when the system is turned off. The sound is independent of compressor on or off or of the air flow selection (defrost, floor only, dash only, etc.) recirculation mode or filter mode.

The car is a 1998 E320T (wagon) with 63000 miles. Theres no debris in the air intake vents on the hood.

Has anyone had any experiance with this before I take it in to the dealer?

Intruder