250 es /sx headlight wiring?

[tri again]

I have 2 wire butchered 250 hondas that
I'd like to put any kind of headlight on.

I got what looks like 11 volts ac out of a blue
wire but all the rest read zero both ac and dc.
and that 11 volts doesn't seem to have enough oomph
to run a taillight.

I know I should harness them both and do it right
but if I can hook a light and switch, maybe evn a house light switch,
and most likely some ducttape for effect, I'd be a happy camper.

Both trikes start and run great except for a hot start issue on one so they
are worth fixing correctly, just not at this time.


ps - also have a 90 that runs great but nothing but cut wires in the headlight bucket and a dangling kill wire with some remnant of the on, off, headlight switch innards that we use to kill it.

Should I just look for voltage with a meter or light on random wires?
Aren't those ac for light?
Stop whining and print a diagram and get out the meter?
Find a new hobby?
Stop riding at night?

any suggestions are greatly appreciated.