Circuit/System Description
WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.
The blower motor control module is an interface between the HVAC control module and the blower motor. The blower motor control module has 4 circuits: a B+ input, a signal input from the HVAC control module, a B+ output to the blower motor, and a low side pulse width modulation (PWM) control. The HVAC control module provides a variable resistance to the blower motor control module to request the selected blower speed. The blower motor control module grounds the blower motor using a low side PWM control in order to vary the blower motor speed.