1988 f350 all lights are on but headlights??????
 

Got every light to come on ( headlamps are still good)have changed the headlight switch and high/low switch has no tilt. Tested headlights no power going to them

Welcome to the forums.

So there is power to the switch, because the parking lights work. New switch, so I'm guess it is coming out of the switch? Time to trace the wire going to the hi/lo switch to see if if it broken? Or start at the headlights switch and trace the wire to make sure power is coming from the switch. Maybe the plug is bad, loose connection? Unplug the hi/lo switch, one of those is 12v with the headlights on. If no power at any, then you know the wire is broken between that and headlight switch.

Got it fixed thanks
 

Had to replace the hi/ low button on floor board thanks for the advice

Typical issue back then with floor mounted bright switches. All the crap/water/etc gets in them and they quit working. They either stick in LO, HI, or the middle=nothing.