If you specifically have issues with trailer ABS power, check fuses F43, F25, and F26 in the passenger-side fuse box. Power Feed:
In a 2019 "New" Freightliner Cascadia , trailer light fuses and relays have largely been moved from traditional firewall locations and are now distributed across several key modules, primarily the and SAM Chassis . Primary Fuse Box Locations 2019 freightliner cascadia trailer light fuse location