When Elias produced the part, she reached under a workbench and pulled out a heavy, grease-stained binder. The cover featured a faded diagram of a rectangular box with dozens of pin connectors.
These manuals cover installation, safety, operation, and fuse replacement:
: Features a built-in battery monitor that shuts off 12V consumers if the voltage drops below ~10.5V to prevent deep discharge. Service & Maintenance Procedures
: Designed for 6-cell lead-acid or lead-gel batteries with at least 55 Ah capacity. Protection
All of this is impossible without the reference designators from the manual.