I use the relay kit . I've had a couple of Dart melt the plug terminal at the switch due to amperage heat.Plus your lights will be much brighter with the relay kit. I used this cheap one on Ebay with good luck but there are better more expensive ones out there . 2-Headlight H4 Headlamp Light Bulb Ceramic Socket Plugs Relay Wiring Harness Kit | eBay
