The blower motor resistor on the Chevy Malibu controls the electrical current to the blower motor. A blower motor's speed depends on how much electrical power is provided. Increased electrical current increases the blower motor's ability to rotate and blow more air.
The blower motor resistor is usually found under the dashboard near the blower motor. It is configured as a set of coils mounted on a non-conductive tray. The set of coils are of different sizes and thickness. The thinner wires have less resistance, which allows more current through and increases the fan speed. A thicker wire has more resistance, which decreases the fan speed.