Could be the evaporator fan motor about to fail or the evap fan blade touching something. If the fan is controlled by a door switch, opening the door would deactivate the motor and the noise would stop. Depress the door switch and see if you can locate the exact source of the noise.
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Could be the evaporator fan motor about to fail or the evap fan blade touching something. If the fan is controlled by a door switch, opening the door would deactivate the motor and the noise would stop. Depress the door switch and see if you can locate the exact source of the noise.