Headlights and hazards kill my truck

So one day I was driving like normal truck running fine then bam no power. It just stopped no chugging no nothing. I replaced the crank and it sorta helped. It idles super rough and then fine a few seconds then rough. The weirdest thing is that if I attempt to turn on the headlights or my hazards OFF I repeat off (it only runs that way and won't start with them off like normal? So what the heck. I tried revving up the engine and turning them off and it doesn't help just dies.