Read this first: This covers safe, layperson-level checks only — switches, fuses, connections, and indicator lights. It will never ask you to open an inverter, work on 240V wiring, or handle a damaged battery. If a step says to call a professional, that's a hard stop, not a suggestion.
What's happening?
Pick whichever best matches what you're seeing. If more than one applies, start with whichever is most urgent — you can come back and check another after.
Checklist
Work through in order — each step usually rules something out before the next makes sense. Tick as you go and add a note if you find something.