Remote light wiring

This is a little tricky because there are a few details left out. However I can attempt to guide you in the right direction. First off you would not need to worry about any current draw when the switch was off. regardless you are correct in having a concern about the 150ft run. If the fog light is only 5 amps that is not really that much current but for safety reasons I would still use a relay. the coil of the relay which will be all that is being drawn off the switch as well as the 18ga wire when the switch is on is 150ma (or .15 amps), which is fine. Now the wiring of the relay depends on several factors. I will give the most likly scenerio. we are dealing with 12volt DC so use a standard 12volt automotive SPDT relay. If you have 12v + at the switch connect that to one side. connect the other side to the 18ga wire that goes to the gate. Connect the other end to terminal 86. connect 85 to 12v -, the relay will only be drawing current when the switch is on, and very little at that. Now connect 30 to 12v +, then connect 87 to one of the fog light wires. connect the other foglight wire to - and it will work fine. Make sure to fuse the wire at terminal 30 as that is the main power, we don't need any smoke shows. Use a fuse with a rating slightly higher then the draw of the fog light and that will be sufficient. good luck.

Thank you.  This was just the information I needed.

You are welcome, let me know how the project turns out..unless of course theres a fire. Kidding, the 25 cent fuse will protect from that. I remember years ago when I finally grasped the concept of how a relay works. Being in this business basically for every $1.50 relay I install I can charge from 30 dollars and up. In addition I can make a relay do virtually anything I want without needing a diagram. I would advise anyone who enjoys tinkering with electronics or as a career to learn relays. best of luck.