I have a 1969 f100 the shop I took it to pulled wires under the dash. I was able to get most everything fixed but I haven't problem with my brake lights, when I stepped on the pedal my light come on with my dash lights. But when I have the headlights on I don't have brake lights. Any idea of what is going on would help

 

You have a bad ground to the rear lights. The rear lights should have 3 wires, taillight wire, brake/turn wire, and a ground wire. See where this ground wire goes. It should tie in with the reverse lights also, both sides, and then it might bolt to the rear frame. It must have continuity back to the negative of the battery. If you can't find where it grounds, you can go ahead and ground it to the rear frame, and then run a short wire from the frame up front to the battery negative.

 

Thanks I'll check that out after the snow leaves