As you do these days, I asked AI. At the end of a long "discussion", it came to this conclusion: "The interesting part is what that tells us about the wiring: The plate light is definitely downstream of the "Control Unit" fuse. The tail/running light is also downstream of that fuse (since it went out too). The brake light is not downstream of that fuse (since it continued to work). The engine ECU, dashboard, immobilizer, and engine management are not dependent on that fuse for their primary power supply (since the bike ran normally). So your real-world fault has given us more information than the owner's manual does. The fact that shorting the plate-light wires blew the Control Unit fuse rather than the Lights fuse is particularly revealing. It suggests that Ducati's naming in the owner's manual is functional rather than descriptive: the fuse may be supplying a rear-light control module or a switched lighting output from a body-control unit, not simply "the ECU." From a diagnostic standpoint, I'd be reasonably confident that: The fuse is protecting a low-current controlled-lighting circuit. It is not the main engine ECU fuse. Ducati's label "Control Unit" is somewhat misleading if interpreted as "engine control unit." Given your observed behaviour, I would trust the evidence from the bike over any generic assumption about Ducati terminology. Your bike effectively proved what that fuse actually does."
