Genuine OEM Audi Interior Heater Blower Motor Regulator, part number 3C0907521E. This electronic module is crucial for controlling the fan speed of the vehicle's interior heating and ventilation system. It is typically located near the blower motor assembly. The regulator ensures precise adjustment of airflow for optimal cabin climate control. Weighing 0.182 kg, this component features a finned heatsink for efficient heat dissipation. Choosing a genuine OEM blower motor regulator ensures correct electronic calibration and signal characteristics, preventing erratic fan speeds or complete blower motor failure.