Hi @cootertwo , looking at the circuit diagram I found here, having a circuit breaker switch at pin 10 of the instrument panel connector might do just the trick of going dark completely (which would work for me as well).
So, where is that elusive instrument panel connector...?
Ah... I just noticed the diagram I linked to has a very small "C20XB" in the small print, so that might refer to an older version of the bike...
I couldn't find the correct connector (even when consulting the correct circuit diagram for my bike), so I went to try someting else. Initially I thought of adding a switch to the wire going to the headlight fuse, but on my 2016 Roadster, pulling the headlight fuse also cuts the power to ignition switch, so you can't start the bike without it... bummer...
So, according to the circuit diagram, a blue wire from the starter relay directly supplies power to the headlight dipswitch. If I could put a switch in that wire, both headlights are without power. If you follow the wiring loom from the LHS handlebar switch block to under the fuel tank, you'll see it ends in 10-pin connector. To figure out which of the wires is the correct one, I hooked up my multimeter (in "beep" mode) between the starter relay blue wire (the one in the middle of the connector) :
and use the other probe to check the wires on the connector I found under the tank. I started with the blue wire and bingo!
The LHS switch block wiring loom had plenty of lenght for the blue wire's counterpart to be cut (the counterpart on my bike is blue/yellow (or yellow/blue?)).
So, I bolted an extra switch on the handlebar, hooked it up to the blue/yellow wire and now I can finally switch off the headlights
and start the bike.
Note: this only switches off the main headlights, so not usable for going completely in "dark mode"...