A howling or groaning noise from the glove box area of the dash when adjusting the volume settings of your ac/heat settings is typically the blower motor assembly.
Always ensure that leaves and debris are clear from the cowl area of the windshield base, as this can ultimately end up in the blower motor casing and cause а noise as the wheel of the blower motor is spinning.
Caution for the Air Bag Circuit connectors (they are a bright yellow and, typically for this service, do not require unplugging). Disconnecting the battery for every service or repair that you may be performing is always a good measure. Using a battery saver will ensure you do not lose radio presets.
Denso OE Parts are always recommended for Japanese Imports.
When replacing the blower as an assembly, it is best practice to replace the related blower resistor, as they work hand in hand.