Good point, it should. My lights are halogen, 55W each, so I needed a relay, they didn't have inexpensive LEDs when I bought these back in 2008. You could try wiring it direct and see what happens. Worst case scenario is a) you blow the fuse on the truck or b) the lights don't get bright enough due to voltage drop over distance. If it doesn't work you could always add the relay. Of course relays are only a few $ so not that much work to just include one from the get-go. In other words, it will definitely work with a relay, it might work without one. No harm in trying though.