The KC HiLiTES 6315 is a pre-terminated relay harness for two auxiliary lights. The manufacturer's product page describes a kit with a 40A relay, an illuminated rocker switch, fuses, and mounting hardware, allowing quick installation for up to two 130w lights, and the kit is rated to handle up to 260w. Its weatherproof 2-pin Deutsch connectors let you plug the harness straight into compatible KC lights rather than splicing bare leads. Compared with a DIY relay setup, the value is that the relay, switch, and fusing are matched to KC's two-light wiring layout. Owners on user forums have reported that a generic 4-pin relay can light only one lamp, so the purpose-built relay is the safer choice. Buyers who later want two more lights can add the manufacturer's 6316 add-on harness.
This kit is not vehicle-specific. It is a universal harness meant to power any two KC lights from one switch, so the main fitment questions involve mounting positions and beam rules. The manufacturer's install sheet says to aim driving lights so the top cutoff sits near the level of your high beams, and it notes that some states require fog lights to be switched with the low beams. Searching for a KC 6315 relay harness install, a Deutsch connector wiring kit for two driving lights, or a 40 amp relay rocker switch harness for off-road lights will bring up the same parts. The installation process is straightforward. The relay goes close to the battery, and the power wires are the last connections made.
The manufacturer rates this kit for two 130W lights, or 260W total. For more lights, the manufacturer offers its 6316 add-on harness, which includes a 40A relay and works with the 6315 to operate two additional lights from one switch.
The manufacturer's install sheet says to mount the relay close to the battery with the terminals facing downward. Per KC support comments on user forums, the relay should sit upright to prevent water from collecting, and close enough to the battery to avoid stretching the wiring.
According to the manufacturer, some states require fog lights to be switched with the low beams and driving lights with the high beams. The white power wire can be connected to the matching beam circuit to meet those rules.
Owners on user forums report that the KC relay has two terminals that both act as pin 87 outputs. A standard 4-pin relay may power only one lamp if the harness runs both lights from parallel 87 pins, so the included KC relay is the recommended choice.
The manufacturer markets this harness as an easy install, and the included screws, wire ties, and splice connector cover most of the hardware. Plan for a drill to make the switch hole, since the manufacturer's sheet calls for a ½" hole when no switch panel is used, while an older version of the instructions lists ¾". Mount the relay near the battery with its terminals facing down, then route the yellow wire to the positive battery terminal and the white wire to positive battery or an accessory 12V source. The manufacturer says to connect the yellow and white power wires last and not to splice them together. The switch must be grounded to chassis or the negative battery terminal for its illumination to work. Owners on user forums say that the self-tapping screw included in the bag is the intended relay mounting fastener.
