Headlights go in and out..started tonight
1993 Chevy C1500

 

I would check wiring, and especially check the grounds relating to the headlights. According to the diagram here, you should have 2 ground wires going to the chassis:

Without Daytime Running Lamps (DRL) — 1993 Chevrolet C 1500 Truck 2WD V8-350 5.7L Service Manual | Operation CHARM

That may not be the one for your truck if you have daytime running lights, but you can poke around and find that diagram.