36 pickup head lights quit working!

[rottenron36]

My 36 pickup head lights and tail lights, quit working over the winter rest. They have been working fine for 5 years. Stock switch at the steering box, 6 volt posi tive,new wiring harness when restored. I need to know where to start, testing things. I hoping to not take the switch apart as it is a bear to work on. Power at the fuse, under the dash. Thanks for looking, and any advice. Ron