Fan Speed Control
WARNING: This page is about a different car, the 2011 Suzuki SX4. However, it is still accessible from the selected car via links, so may be relevant.
HVAC control module calculates the target blower fan speed based on signals from the temperature selector, inside air temperature sensor, outside air temperature sensor, ECT sensor and sunload sensor and compares it with the current blower fan speed input from the blower motor controller to control the current blower fan speed to the target level.