Spot lights - wiring diagram - hilux4x4 The diagram below shows a simple wiring diagram for connecting spotlights to work together with your high beams. All you need is some wire and lugs, a 12V 4 Pole relay and two fuse holders with the correct fuses. Just make sure that you use decent sized wires and a proper fuse holder for the connection of the power between the battery and the How to Wire up Lights in Your Hotrod! Very small considering todays lighting requirements. Then add in the years of corrosion at connections, wear at the light and dimmer switches and the amount of resistance in the circuit goes way up. So, use the right size wire. (See the lighting diagram below.) Tip: You can buy trailer wire cable to run wiring to the back of a car. How to Wire Lights on a Trailer | Wiring Diagrams Do you need better ideas on how to wire trailer lights? There is always a solution fo that, even if there are absolutely no provisions for trailer lights. In case you are electrically inclined or have a rough idea of how to wire trailer lights, you might consider splicing into your existing wiring. How To Wire Driving/Fog Lights – Moss Motoring Aug 02, 2012Before cutting any wire, a good diagram is in order. Draw a diagram on plain white paper with wire gauge noted and colors identified. Each component must be labeled. This wiring diagram will stay with the car so make it neat and easily readable. Pictured is my wiring diagram for installing two fog lights with fuses, a switch, and a relay.