If wired this way they will come on when ever you want. That is why you attach that wire to a parker wire because they are always on when you low and high beam are on. If wired exactly the wau described then they will turn off when parkers/headlights turn off either by the switch or when the ignition is turned off and you open the door. For the parker wire I use one of the illumination wires from the other dash switches (A/C, Demist or hazard). To find out which one to use connect you test light to an earth (any metal surface on the car will do). Then put the other side to a wire that you think will get power when the parkers turn on. Once you have selected the wire, turn on your parkers. If the test light, lights up when you turn your parkers and turns off when you turn them off then that is the right wire to tap into. I hope this small essay hasn't confused you and it makes sense for you.