I have a 2000 E150 5.4 chateau, after towing my trailer the other day the same thing happened to my van. Already replaced the light switch no difference, harness and wires seemed fine. Do I need to take the harness completly appart to tell if any thing is wrong? Headlights work fine as they should. running lights only come on in the wrong position, a little toward the headlight side of the switch. Exactly the same as ironpants. Flash to pass does not work either. I did have a blown fuse for the right tail light. I have also tested the large fuses in the power dist. box, and moved the relays arround. is it possible that the wires are bad elsewhere?