OEM Front rear upper interior fan resistor fits BMW X5 F15,F85 xDrive 35 i +more

image is example only, brand may vary

A blower resistor in a car plays a crucial role in controlling the speed of the blower motor used for the vehicle's heating and air conditioning system. It is an electrical component placed in the blower motor circuit to regulate the amount of voltage and current supplied to the blower motor. The resistor achieves this by providing different levels of resistance, which in turn alters the blower motor's speed.

Typically, a blower resistor consists of multiple resistors, each having a different resistance value. By selecting various combinations of these resistors, the blower resistor can create distinct voltage drops across the blower motor and thus control its revolutions per minute (RPM). This allows the driver to adjust the airflow and temperature settings inside the car's cabin according to their preferences, providing comfort and convenience while driving.