My fog lights only operate with the switch. I had a Grand Am before that had the fog light switch tied in with the light sensor so that the fog lights only worked when the full strength headlights were on.
O.K. I misunderstood your post. Annoying on the Grand Am. Explains why you don't see alot of them running with just fogs and drls or just fogs.
I learned something in the process of having my harness replaced. Sometimes
you need to have both replaced. My left kept blowing even after the harness was replaced until I told them to do the right too. The left bulb blew once more, but that was due to man-handling. No problems now. Do not ask me why on my GXP the right and left BOTH had to be changed if only the one side was blowing (e.g. my left). Same fuse? Dunno.