Anon
My Harley did Weird stuff on our St Paddy's day Kilt run. I had intermittent engine light but then Speedo stopped, tach still worked. Died at stops but always restarted and idled. Tightening battery and ground connections; and one to starter fixed it.
Also possible rain water got in, or got wet while washing. In which case, display works, but you cant see it. Allow to dry 3 days, then seal it.
My waterer got that way, had to soak display in alcohol. Then, I sealed it with siliconized latex..
. Remove fuses , one at a time, check them and replace. If you have ATOs, as probably, just Look at them. On old glass 3AGs, often element would open Inside cap from vibes. Looked Fine, but didn't Ohm-out.
Often there is corrosion on fuse clips. May want to tighten clips Slightly. My old Honda would suddenly stall, it wasn't ign or kill switch. Fuse box had pressed-in bus rails, they worked loose. Had to solder them.
adam
look for shorted or grounded out wiring. Need a multi meter and or a test a light. Shop manual will show you the wiring diagrams too.
Exoplanet
Betcha the ground or hot side ain't got continuity with the battery 'cuz something's loose or corroded or shorted or open. Ya gotta take off the covers and the tank to really check dem electrics, dude. Check the fuses. Gitcha a multimeter.