Originally Posted by Biodiesel300TD

Like I stated in my first post. Pull the rubber cover off, and give it a visual look to see if anything is obvious. You might have to pull it off and really look at it on the bench. It sounds like a ground problem. The ground wire in the combo switch could be loose or the wire partially broken. The problem is somewhere in the swtich. Since you've replace the hazard switch and relay, and the bulbs work with the hazards. Intermittent electrical problems are usually bad grounds or connections.