I also used a $4 automotive relay for the 3 light mod. The reason I chose this over a diode is that I didn't want the extra load on my handle bar switch. The relay works great and is easy to install. I also used a relay for my backup lights. I used a 55w tractor utility light and tapped into the reverse inicator switch for the activation coil. With both of these I don't have to worry about any additional current draws.