1996 Dodge Ram headlights

1996 Dodge Ram V12 Two Wheel Drive Automatic

i was driving down the road for about 20 mins and my headlights started flickering then then about five min later they cut off so I shut the switch off and wait about 10 min and turn them back on and they work and it starts all over again I have replaced the headlight switch with new ones about 3 times and it still does it what do I try now before I replace all the wiring