I already told you that you don't need a relay . I have a relay on the power supply side of my head light switch , but it is there so that everything turns off with my key without overloading that. That guy has a relay because he did not want ac and dc running thru his switch . so he wants to switch the relay and run the turn signals with dc and run the ac to the headlight thru the relay . I don't think there is much of a point to this but that's what he wants. the way you are talking about it differant then both mine and his. You want to run the output from the switch to trigger the relay and use the relay to carry the load of the headlight . this is all well and good but that switch is designed to carry the load of headlight so it's kind of pointless.