The only way I can use my fog lights is with the "parking" or head lights on. This illuminates the tail lights. I think using the parking lights and fog lights as Daytime Running Lights is dangerous because you don't have the maximum possible change in tail light intensity when you are braking.
I just wish my dealer wasn't stone walling me about turning them on. My dealer's service department is a bunch of Bozos.
Bob Fennema
2004 2500 SWB