No... Fogs turn on separately and they are not used to supplement the headlamps. They are called "Fog" lights for a reason. They are to be used in foggy and other low visibility conditions. Please don't be like everyone that keep their fogs on at all times. The fog's generate a good deal of glare to oncoming traffic.I guess I was under the impression that they were supplementary to the headlamps and that they were turned on at the same time. Is that not the case?