Installing an Auxiliary Fuse Block in an XJ

If you’re any sort of off-road enthusiast, you’re likely going to be adding a slew of electrical accessories to your vehicle, ranging from radio equipment to driving lights. What most vehicles lack is a dedicated fuse block with which you can safely provide power to these 12V accessories.

Installing such a fuse block keeps your aftermarket electrical system tidy, provides dedicated power, and takes a lot of the hair-pulling out of the wiring process. No more jamming wires into the factory fuse block, or cluttering up your battery posts.

Blue Sea Systems has a variety of different models. We chose the ST Blade, part number 5026. Also pictured next to brand new military-style battery terminals.

An example of a cluttered battery terminal that could benefit from an auxiliary wiring system. Photo graciously provided by Jason West from Jeepin Outfitters. Thanks, man!

To accomplish this, we purchased a Blue Sea ST Blade Fuse Block. Blue Sea Systems specializes in electrical components for marine applications, but their products are also extremely ideal for overland vehicles and RVs.

To supplement the auxiliary fuse block, we replaced our factory battery terminals with military-style. These battery terminals have a secondary lug that better accommodates multiple connections to the battery posts.

What you’ll need:

  • Blue Sea Fuse Block
  • Mounting Plate (5×8 inches)
  • 10′ Red 4-Gauge Wire
  • 10′ Black 4-Gauge Wire
  • Box of 3/8″ Ring Terminals
  • Shrink Tubing in Assorted Sizes
  • 3/8″ Techflex Braided Sleeving (optional)
  • Set of Military-Style Battery Terminals

 
Unfortunately, the engine compartment of the Jeep Cherokee is a tightly-packed suitcase that makes it difficult to add pretty much anything. The best available space we found to install the fuse block in our 2001 Cherokee was on the inside lip of the driver’s side fender. From there, you can install a flat metal plate that extends toward the brake fluid reservoir. This is a great spot, because it’s extremely accessible, out of harm’s way, and right next to our route through the firewall. The only potential problem is that the fuse block comes very close to the hood when it is down, so take whatever precautions you need to ensure that this is not the case.

Once you’ve mounted the fuse block, cut your red and black 4-gauge wires to length. Install ring terminals, and Techflex if you so choose. Techflex is not required, but adds a good amount of protection to your wires, and gives off a nice professional appearance. After you’re finished preparing your wires, you’re ready to route them back to the battery.

 

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The factory battery terminals are permanently attached to the positive and negative wiring. You’re going to want to cut those suckers off. Replace them with a couple of 3/8″ ring terminals, and you’re ready to install the military-style battery terminals and hook everything back up, including the positive and negative leads to the new fuse block. The auxiliary fuse block should now be hot, and ready for your accessories.

 

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As you can see, this is a very easy process, and it only costs around $100. If you’re outfitting an off-road or overland vehicle, and plan on adding any number of 12V accessories, this should be one of your foremost modifications. Do it right the first time!

Our new fuse block freshly-installed, juiced up, and already providing power to our IPF driving lights.

Our new fuse block freshly-installed, juiced up, and already providing power to our IPF driving lights.

Military-style battery terminals cleanly installed over the battery posts, providing power to vehicle, winch, and fuse block.

Military-style terminals installed over the battery posts, providing power to vehicle, winch, and fuse block.