56 Loboy Headlight Wiring

I have a 56 loboy, 6 volt positive ground and I am hooking up the headlights, there are 2 wires coming out of the hood on each side, so I hooked 1 to the light terminal and 1 to ground , blew the fuse, took the ground 1 off and the lights work, grounded thru the mounting, why is there 2 wires when lights only appear to need 1 to work, should I hook both of them to the light terminal or just leave 1 off.  thanks Darrell