Trace the start/charge circuit from the ignition switch through the SAM Cab to the starter solenoid.
Most Cascadia electrical "gremlins" are caused by on the frame or the firewall. Always check the grounding section of your diagram first. diagrama electrico freightliner cascadia pdf verified
Detailed views of connectors (like the 21-pin or 31-pin SAM connectors). Trace the start/charge circuit from the ignition switch
Standardized Freightliner abbreviations (e.g., BR for Brown, DGN for Dark Green). BR for Brown
Use the SAM Chassis diagram to check if the module is sending power to the headlight harness.