Fog Light Wire Harness | AutoPartsWarehouse A fog light wiring harness must include a wire harness, a switch, and a relay. Choose a pre-terminated wire harness if you do not want hassle in connecting the wires to the other components in the set. Also, set descriptions indicate the number of fog lights that the wire harnesses can accommodate. Amazon: fog light wiring harness HUIQIAODS H11 880 881 H9 Fog Light Lamp Wiring Harness Socket Wire Connector With 40A Relay & ON/OFF Switch Kits Fit for LED Work Lamp Driving Lights Etc. 4.7 out of 5 stars 10. $17 $ 17. 99. Get it as soon as Wed, Aug 14. FREE Shipping on orders over $25 shipped by Amazon.