Pop quiz, hotshot. (Hopefully some of you will catch the “Speed” reference.) You have several lighting or other vehicle accessories that you need to get wired into your vehicle. You need fused power sources, and you need relays and switches. What do you do?

Well, you could install individual wiring harnesses and have a spaghetti-like mess of wires crawling off of your poor battery. You could also spend $400-$600 for a high end solution, such as an SPOD or Switch Pros setup. Or, if you’re like me, you might just be happy with a lower priced, but well thought out system….such as can be found in the Waterproof Fuse Relay Box.  What is it? Well, it’s named fairly appropriately.  😉 According to the maker of this little gem, “Waterproof Fuse Relay Box is the best option to control your accessories and clean your messy vehicle wiring for a low affordable price!”  I think I’d have to agree with that statement.

The Waterproof Fuse Relay Box (which from here on out, I’ll lovingly refer to as WFRB) is a no frills, yet very capable method for installing a variety of switched and/or always on electronic accessories in your vehicle. It’s simply a waterproof box (you knew that already, because it’s in the name) that has fuses and relays (yeah…that’s in the name as well).  Five relays, and ten fuses, to be precise. Actually, there are eleven fuses, if you consider the main 60 amp fuse that ties the positive lead to the battery and protects the whole setup.

The five 30 amp fuses are tied to the five relay circuits for your switched accessories, and the five 15 amp fuses are for your constant 12v circuits that are always hot. Those are default values of course, and you really should make sure that your fuse amperage is adjusted as necessary for whatever it is you are wiring.

Looking at the under side the WFRB gives you a sense of the attention to detail that goes into making it. Besides it’s artistic flow of carefully bundled colored wires, you can see the great care in the waterproof plugs used for the wired connections and the empty holes in the box. You’ll notice right away that there are two wires of each color. One is 12 gauge, and that’s to connect to whatever auxiliary component you wish to power with a switch – a light bar for example – and the other is a 16 gauge wire that would be run to a switch. The color coding makes it easy for install. Red switch wire controls the red accessory. Easy, right?  There are five additional 16 gauge wires for the constant 12v accessories, like a CB, that you might want to always have power, even when the vehicle is off.

Since switches don’t come with the WFRB, you’ll need to source them separately. That’s actually a good thing, since there are so many different types of switches and preferences on installation. I chose to load a Daystar switch panel with OTRATTW switches. That stands for “Over the river and through the woods” for those of you not aware. I went with their latest Contura 14 (XIV) rockers with led lighting.  They are a little on the expensive side, but you can easily find similar (and less expensive) alternatives with a quick eBay or Amazon search. I have mine wired into the dimmer circuit in my 2015 Jeep JKU Willys Wheeler. When the rest of the interior lights are on, so are my green LEDs in the switch lights, and they dim just like the factory lighting in the vehicle. When the switch is engaged, the graphic is lit up with the red LED to make it clear which is on.

The WFRB does ship with a sample wiring diagram, that gives you a basic idea of how the wiring is intended to work. Like most things, however, you can customize to fit your particular application. For example, I am actually using one of the constant 12v wires to power my switch panel rather than feeding the switches from an ignition power source. I explain this is more detail in the video below if you’d like to know more.  This is the wiring diagram for my current setup (at the time of this writing anyway). I am using two switches for lighting, two switches to enable in-cabin winch controls, and also feeding power to my CB. Again, I spend quite a bit of time explaining this diagram in the video. I still have several unused relays and fused circuits…so plenty of room to grow.


You can find out more about the WFRB by visiting their FaceBook page. He can also customize WFRB to meet your needs, such as increasing wiring lengths, or building it to be negatively switched. Check it out!  And now…the video. Enjoy!

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  1. Have you had any problem with condensation inside the fuse box? I have been having constant problems with it.

    1. Not to my knowledge. Have you contacted the manufacturer? We can try to help you do that.

      1. No I have not yet, there was enough condensation continually gathering inside the box that there was actual liquid coming out when I would open the box. It has caused rust issues and some relays will no longer work.
        To be clear I did not order from the link you provided. I am just trying to see if anyone else has had issues with this brand of relay block, I ordered direct from the manufacturer.

        1. No one else has reported and issue to me. I would definitely reach out. It’s billed as waterproof so it should stay dry no matter what. Can you post a pic of where it’s installed?

  2. I would really love to be able to get one of these for my 2015 JKU. I sent him a message but not sure if this person is still making them. I’m praying they are since it’s exactly what I need for my rig.

    1. I haven’t talked to the owner in quite some time. If you cannot reach them please let me know.

  3. Have not been able to contact the owner. Would really love to be able to get one for my Kubota RTV and Tractor. Is he still in business or has he changed names??

  4. If the constant 12v is used to power the switches, if I turned everything off and didn’t come back for a few months, wouldn’t that drain the battery?
    Being that the 12v constant is on the switch, when the switch is off, than the 12v constant is off as well?
    I’m misunderstanding something, just trying to make sense of it.

    1. The 12V is always there. There are many circuits in a vehicle like this. That 12V would only drain the battery if there was a short or if the switch is left on. Think of it like water at your faucet. As long as the handle is closed the water doesn’t flow but it’s there. Same concept.

      I would recommend putting a vehicle on a trickle charger if you plan to leave it for months or disconnecting the battery. It’s better for battery health.

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