I have been getting a lot of questions about how I wired my light in so I made a little drawing up for others to use.
For me I take wiring very seriously, as a few pennies pinched can cost you your vehicle very quickly and when I do something I never want to do it again so do it right the first time.
For things like lights I only use parallel bonded, jacketed wire or (duplex brake cable) for everything either 12/2 for the high current side of the relay from the battery to the lights and 18/2 for the switching side of the relay. It keeps everything very clean and easy to route and I HATE split loom.
All my connections into the factory harness are soldered and then heat shrinked, this just ensures that I never have to worry about corrosion on my wires later and that the factory harness is not weakened in any way. I never cut a factory wire to do this I just strip 1/2" of insulation and solder to the wire.
Everything on a vehicle at some point is going to have to come off or be moved so I always use weather-pack connectors at the ends of all connections to lights, fans, compressors, and behind the dash to make easy removal when the time comes without having to cut wires to do things. I also use weather-pack style HELLA relays and fuse holders. I had 10 years on my last truck and I never had to rewire anything or even blew a fuse.
Here is how I have my Fog lights, off road lights, backup lights, and train horns wired in.
The below diagram is for 1 PAIR of lights or up to a 30 load on the relay.
As for the back up lights what I always do is run 3 wire cable (#12) to the back of one of the tail lights. An old extension cord works very well for this. I mount the relay behind the tail light also. So using an old extension cord you will have 3 wire colors (white,green, and black). I run the white wire to the battery (via the fuse) and then connect it to pin 30 on the relay behind the light. The black wire I solder into the back up light circuit and connect the other end to the bottom (auto) of the switch. The green wire gets connected to pin 85 on the relay and a small jumper from pin 86 to the mounting screw for the relay on one end behind the light and the center pin on the switch. From pin 87 you run more #12 wire to the lights of your choice, and ground the lights near the lights or back at the mounting screw for the relay which is what I prefer. This way you only have to look in one place if things ever stop working.
This will provide you with backup lights that will come on automatically with your factory back up lights, all you need to do is run a power wire from a keyed source light your lighter plug to the top pin of the switch to allow for manual operation of the back up lights.
we use the 1R 0750's on the cats on our ship as primary filters and the 0749's as 2ndarys i got like 30 of those in my stores heh
