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JK auxiliary switch and relay project

This is a project I completed a few months ago, but figured I would share it here. I see mostly mechanical projects in this forum, but I'm not mechanically inclined :smile: so here is my electrical project writeup.

I wanted to add four lighting-based circuits to my Jeep. I really like riding trails at night, particularly in summer, but the stock lights just weren't cutting it.
  1. Light bar above windshield
  2. A-pillar / windshield lights
  3. Rock lights (or in my case, "stick and stump lights")
  4. Rear lights

I wanted the switches to be in an intuitive spot, so I can quickly reach for them without thinking. For me, that meant left handed operation (headlights, high-beams, fogs, blinkers all toggled with left hand, after all). The logical place for these switches then, was in the A-pillar. I picked up a 4-switch A-pillar switch pod online that matches the stock A-pillar pretty well.

For the switches themselves, I went with a company called Cruiserheads. Their switches feel solid and I like their appearance, and they'll also make you a custom switch with whatever logo and text you want. Most of the illuminated things in the JK are green, but I was worried I wouldn't be able to match the exact green, so I went with white.

I didn't want all the amperage of the light circuits passing in and out of the firewall, do I decided to run low amp lines to the switches which activate relays in the engine bay. Safety first ;-).

Enough with the text, it's picture time. At least on my screen, the forum software is stretching the images so you might need to right click them and open in a new tab.

I cut out the holes for the switches and placed them in the order I wanted them. This pod and switch combination makes for a tight fit, but I think it looks nice.

Then I wired the switches.
  • Black - negative
  • Red - positive
  • White - positive output (this is what triggers the relay)
  • Green - variable positive from interior light dimmer circuit
The wires are all terminated a few inches away with bullet connectors, making it very easy to remove this A-pillar assembly if I want to change something out.

Next up was the fuse and relay housing. I could have gone with something like an sPod, but decided instead to make my own. Perhaps the most difficult part of this project was finding an appropriately sized box to put everything in. I finally found a tackle box at Sportsman's Warehouse that fit on top of the battery perfectly. When the hood is closed, it's snug and hasn't moved at all over the last several thousand miles. One problem, though - the tackle box had internal structures in the way. I simply used my soldering iron to cut them out.

Then I ran wires from the DIY fuse box. 0ga positive and negative leads to the battery, 4 black/yellow pairs as switched lines out, 1 black/red pair to power the switches, and 4 white lines coming back from the switches to toggle the relays.

Then came the fuse block. First up was an inline 100amp fuse in the event that the fuse block fails. Then simply hook the positive (blue) and negative (black) feeds from the relays to the fuse block and add fuses of appropriate amperage.

The fuse box sits snug on top of the battery.

All that's left to do is wrap the white relay toggle lines in conduit.

And here it is in action. The right side of the switch (the text side) is illuminated via the interior dimmer circuit. The left side is only illuminated when the switch is active.

I have a similar interior 5-circuit auxiliary project if anyone is interested, but this is getting lengthy :smile: