headlights not working

I don't post here often although I scroll through threads daily.
Maybe yal can help me out a little.

67 barracuda.

I had a halo kit put into the car. Worked fine for maybe 100 miles.
Now the lights won't come on. Halo's work fine, parking lights work fine tail lights work fine blinkers work fine.
No fuses are blown. No parasitic draw on battery when the car is off.
checked several grounds and they appear fine, loosened and re tightened.

Battery shows 12.59 not running.
When this happened my battery died and I lost all lights on the ride home. Jumped it and it drove home.
car in off position I get 10.5 amps at rear of altenator. car running I get 20 at rear of altenator.

I unplugged the 3 prong for the headlight and I get nothing from that.
Would this be a headlight switch problem? Even though parking lights and halo's work? Brights switch on floor?
How would I test the headlight switch and what amperage from where should I be getting?