I've since disconnected them, but you can wire them up to a switch that controls them independently or you can wire them to the marker lights so that they flash with the marker lights. They should definitely not be used instead of headlights. I would turn them on around dusk and then switch to the headlights when it got too dark. Of course when I switched to headlights they would stay one too since the marker lights would stay on too. I may wire them back up to an independent switch inside the car sometime, but I'm not going to splice them into the markers again since that's a brand new forward lamp harness I've got in there now.