Running light issues

[goodemj]

I have a 1969 Chevrolet k10 LWB pickup, I was leaving a friend's house and when I turned my lights on I had no dash lights and so I tried to investigate but the dome light wouldn't turn on either. So I got out and I have no running lights, but the headlights, turn signals and backup lights all work.

I drove home and as I pressed the brake pedal the dome, dash and running lights lit up but only with the brake pedal pushed in.

I suspected the headlight switch so I replaced it but it didn't fix anything. All the fuses look fine and the bulbs are fine because everything lights up when the brakes are pressed.

I'm stumped, has this happened to anyone else before or does anyone have any advice to help me solve this problem so I can drive at night again???