How-To Make an Auxiliary Fuse Box

chicknhawk99 · #1 11-03-2018, 06:53 AM

I plan to post pictures just need to get my flash drive back to upload them!

I’ve had been through 3 different auxiliary boxes before I finally decided just to suck it up and build my own. My main problem is I always ended up with more wires than I wanted in my truck because my fuse boxes didn’t have relays and I had no way to mount it in the engine bay.

So during my V8 swap. I had some time to play around with the fuse box from the donor explorer I had. And it conveniently can be place next to the old fuse box in the engine bay. When the original mount is removed. Im still working on a permanent mount to be able to hold both boxes.

So with some extra time while waiting for parts to arrive. I went to the junkyard and grabbed another exact same fuse box as the one from my 99 ranger and 00 explorer, and I also grabbed a random engine harness to body connector (so I have approx 40 wires that can be connected on each side and I can disconnect it from the truck to work on it and do not have to cut any wires.

Well first thing first. I removed all the small blocks from inside the main box, so I could start fresh with an empty box. Separate top of the fuse box from the bottom. You may have to remove the big fuse on side. Use a screwdriver to pry the tabs off and slide the bottom off.

Remove the small blocks not wanted, blue circles, push inwards to let the block slide out.

This is when you have to sit down and think of what you want from your fuse block. Do you want more relays or more fuses? Do you want a lot of small mini fuses or more Maxi fuses to handle more current? Well I wanted a split of relays and maxi fuses. With my setup I ended with relays, mini fuses, and maxi fuses.

Now comes the hardest part of this process. Wiring it all together. Insert the blocks you want into the empty fuse box. Remove the extra pins from the un-used small boxes to insert into the ones that you are using in your big box. This is due to Ford not needing to use every pin and slot to make the vehicle operate, so some fuses do not have pins or wires in the blocks if that makes sense.

Now is the time to find which wires are your power wires and which are going to be your feed, or your switch leg for your relays. For your fuses, this is simple enough, power in, feed out. Since you are making an aux fuse box, I can assume you need to power stuff, so you should already have an idea of what you are power and what wire size you need to feed it with. You need to take this into consideration when you are starting to solder your power wires to the pin wires in small boxes. In some cases, like installing heated/leather/power explorer seats, you need to run 10ga wire for it, so that’s what you need to solder onto the power/feed wires of that fuse.

Start soldering on the power wires that come from the battery, I would suggest to merge wires and solder them together to save space and make it easier to connect to a power source. Every small box had a separate feed on mine. **remember if you have relays, the power for those needs to come from a fuse from inside the fuse box and connect to Pin 30 on the relay**. After I got those in, I had about 5-10ga wires coming out the side of the box where the original fuse was, seeing as I couldn’t get the original sheet of metal they had powering stuff with the original fuse, I removed that and ran my power wires out the side of the box there and extending them long enough to reach a little past the ABS module in the bay.

Moving onto the feeding wires. You need separate wires for each device needing the power since they are on separate fuses. Most were either 14ga or 12ga. This part is simple, just make sure everything is labeled so you know what fuses control what device. I suggest drawing your own wiring diagram and locations of what fuse controls what. If you want constant power to the device, you can run the feed straight from the other side of the fuse and extend the wire out the bottom of the box, try to bend the wire toward where the hole is on the bottom piece you removed earlier. For switched power devices, you need to have your feed coming from off a relay. This is Pin 87 on the relay.

On relays, you have normally have 5 Pins, and you normally only use 4. You have Pin 30, which is your power. Pin 87, which is the feed to the device. Pin 86, which is your signaling wire which is either from a switch or your ignition or anything else that has on/off capabilities. Finally you have Pin 85, which is your ground. So with the same procedure as the power wires, solder and heat shrink in ground wires for how every many relays you have, extend these out the same way your power wires are. I would suggest to merge these wires into one that you can crimp on a copper lug and either connect to the body of the truck or straight to the battery, your choice.

Finally, your fuse box should be all soldered and finished. Time to try and make it look somewhat professional and get the wire management done inside the block and bend the wires to where they are in the hole of the bottom piece, now tape the s*** out of those wires and a couple inches past where the come out the bottom. Now re-install the bottom plastic piece.

With the fuse block now totally back together, you are either run those wires straight to your devices, or be smart and use a multi-pin connector to be able to remove the fuse box to work on it down the road and have more device feeds. This is very simple and if you made it this far, it'll be a breeze. Just connect the feed wires to one of the connectors. Now line it up and extend the wires on the other connector to you devices.

Now once that connector is finished and you installed the other connector in the truck, you can insert the new box into the truck and navigate your wires how you like. I just screwed my ground wires to the body after grinding some paint. My power wires I merged into one wire and used one of the subwoofer amp round fuse to connect to my battery.

Congrats, you should have a working expandable auxiliary fuse box for your truck

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dvrich · #2 11-03-2018, 03:22 PM

Great story. I suppose a step by step explanation for replacing the wiper blades would be only 500 words.

chicknhawk99 · #3 11-04-2018, 07:09 AM

Well seeing as i dont have the pictures to upload yet i was actually trying to explain how to make it work and do it. And actually having something productive to say rather than sarcastic comments put onto everyones threads

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Quote:

Originally Posted by dvrich

Great story. I suppose a step by step explanation for replacing the wiper blades would be only 500 words.

And i guess thats what happens when you get a nail to the head but to each their own

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chicknhawk99 · #4 01-03-2019, 01:08 PM