Unusual Noise As Engine Stops Turning

[anasazi]

When I turn off the ignition key, as the engine coasts to a stop I hear a strange "squawk" from the area of the engine accessory (belt) drive. It's continued for several months, never gets worse or better. It's barely audible from inside the vehicle but obvious if I'm standing in front. Had thought it might be AC compressor but have shut that off and still get same noise. Almost sounds like an air pressure relief but I'm not aware that this vehicle has an air pump.

Have not taken to dealer yet, would like to know of others have had similar experience before the dealer tells me "it's normal!"