Chassis Control Module-Auxiliary
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2020 GMC Yukon XL, 2020 GMC Yukon, 2020 Chevrolet Tahoe, 2020 Chevrolet Suburban, and 2020 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
The K38A Chassis Control Module-Auxiliary is a serviceable GMLAN module. The chassis control module sends the low power commanded duty cycle signal to the trailer brake power control module. The trailer brake power control module amplifies the signal and provides an output that is required to drive the trailer brakes.