Theory Of Operation
WARNING: This page is about a different car, the 2014 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
The Engine Cooling Fan is operated by a Cooling Fan Module. The Cooling Fan Module receives a Pulse-Width Modulated (PWM) signal directly from the Powertrain Control Module (PCM) through a dedicated circuit. This signal varies depending on temperature and other engine inputs to the PCM.