Power Module: Operation
WARNING: This page is about a different car, the 2004 Dodge Intrepid, 2004 Chrysler Intrepid, 2004 Chrysler Concorde, and 2004 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
The power module receives pulse width modulated (PWM) signals from the BCM. The power module varies voltage to the blower motor for different blower speeds based on the ATC software. There are 14 selectable speeds, while the Auto mode provides 256 variations.