I am stumped. Lets see if we can figure this one out. When I pull my headlight switch all the way out on my 88 f150 the headlights come on but nothing else. I have to push it in a little bit and jiggle it and the other lights come on. This would be fine but sometimes when I hit a bump they will go out and I have to jiggle the switch again. I have replaced the switch and they didnt work at all so i put the old one back it. I seen where someone had the same problem and it was a fuse and I checked the fuses and they are all good. It makes no sense to me.

 

You may have a shorted wire or ground that's affecting it, trace down the harness and see what you can find. Check the back of the connector too if the are broken wires, even if it doesn't look like it

 

The wires used to the headlight switch were thin gauged and tend to over heat. The over heating causes the wires to corrode. You will either need to change the headlight switch or replace the wires... possibly both.