Not sure whether this is related to the blower, but when the blower power was reduced, the softer the noise becomes.
The aircon is always use on cold temp (22- 23 degrees celcieus) and never on heater.
The noise can be heard whenever the aircon is turned on to the above mentioned, but didn't try on heat and vent. mode.
Noise sounds like metal object rubbing each other (not whistling but screeching noise)
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