Theory Of Operation
WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) controls the Radiator Fan Low Relay by grounding the Radiator Fan Relay Control Low circuit when it is determined that low speed fan operation is required. When high speed fan operation is required, the PCM controls the Radiator Fan High Relay by grounding the Radiator Fan Relay Control High circuit.