I used the headlight relay harness from LMC truck and it was an easy installation. I put an additional power junction point on the passenger side fenderwell (same type as the one on the firewall behind the brake booster) and ran a 10 gauge wire with a fusible link over to the battery positive. That gave me a good place to use for powering the headlight relays. Then I attached the relays to the radiator support near the battery and ran the cables to the headlights.
The harness I got had really bright yellow wire, which looked out of place, so I put it all inside black split wiring conduit so it matched the other wiring in the truck.
Bruce