Set Condition
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 Powertrain Control Module (PCM) sends a Pulse-Width Modulated (PWM) signal to the Cooling Fan Module to operate the Engine Cooling Fan. The PCM detects that the Cooling Fan Control circuit is above a calibrated voltage for a calibrated threshold of time.