Theory Of Operation
WARNING: This page is about a different car, the 2016 Dodge Durango. However, it is still accessible from the selected car via links, so may be relevant.
The Radiator Fan Module is a smart device which controls the Pulse-Width Modulated (PWM) Radiator Fan speed. The Powertrain Control Module (PCM) sends a PWM signal to the Radiator Cooling Fan Module to control fan speed. The Radiator Fan Module will control the fan speed based on this input. The Radiator Fan Module performs diagnostics on the Radiator Fan circuits. If a fault is detected in the voltage supply, ground or internal fan circuitry, the Radiator Fan Module sends a fault message to the PCM using the same PWM circuit. During normal operation, the Radiator Fan can be operated between 10% duty cycle (Low speed) and 92% duty cycle (High speed).