8.10-Custom Relay and Fuse Panel

When you add accessories, you need to support those accessories with a proper electrical system for optimum performance and safety. In this video I walk you through the process of designing and constructing a relay and fuse panels to hop up your hot rod.
Below are links to some of the parts I used:
Relay and Fuse Block:
www.amazon.com/gp/product/B07...
Relay Terminal Connectors:
www.amazon.com/dp/B01MFEDLM4?...
Bus BArs:
www.amazon.com/dp/B08C9MXVFQ?...
Via Air 40AMP Relay:
www.amazon.com/dp/B000YC7GBU?...

[@KSwapTheWorld69]

I Am Doing This To My K Swapped 69 C10. This Is Now Saved In My "K-Swap" Album.

[@difsid569]

omg you're the only one who could make me understand how a relay works thank you

[@tulpa1940]

This video is a gem. It really helped me understand what I need to do to properly wire my jeep accessories. Thanks!

[@MattsGarage]

Happy to have helped!

[@mikem5475]

Great video. Nice to see the carb is working good

[@RatelLaw]

Thank you for sharing your expertise. Always interesting and informative.

[@nathanrodgers86]

Criminally undersubscribed channel.

[@MattsGarage]

Wow that’s a great compliment! Thanks!

[@tomkrause62]

Save some wire and clutter by jumpering pin 86 to pin 30, and then putting your switch between pin 85 and ground. Saves running a hot wire all the way to your switch and back, while just grounding all your switches to a common spot under the dash. Most modern automotive wiring is done this way, especially stuff controlled by the ECM.

[@MattsGarage]

Thanks Tom. The only reason I didn’t do that on a few of them was to have the 86 only hot when the ignition is on since I was powering the buss with battery hot. But I agree with the principle totally.

[@davidokner5450]

@@MattsGarage can you explain that a little, best video so far to explain a relay ive found! I want to move the rats nest of wires from my interior fusebox to a relay panel but I only want power when ignition is on... TIA!

[@MattsGarage]

@@davidokner5450 thanks! What I was trying to explain was that if I was powering the whole panel with switched ignition, the. I could jumper everything 86-30. Then it only needs one wire to power the whole the panel and cleans up a lot of wiring. But I have that panel on Battery + and I don’t want the 86’s to also we battery + I want them on switched power. In case something grounds out in the middle of the night from a furry beast chewing on the wire, it won’t burn the whole rig to the ground.

[@davidokner5450]

@@MattsGarage Hi, so instead of running the power directly from the battery I'd run a wire from the ignition switch itself and that would be my connection to the 30 blade or main power cable, correct? thanks!

[@MattsGarage]

@@davidokner5450 hmmm. No it would be from your ignition to the 86. If you run ignition to 30, then whenever the switch to ground on 85 opens, you are powering your device through your ignition switch. That could be ok for things that require only a little amperage, but anything that draws a lot of Amps should (in my opinion) be battery + to the 30. The only debate is whether to power 86 from battery + or to power 86 from ignition hot. I was just saying I prefer the latter but I admit the former is cleaner in the sense that you have fewer wires running to the panel. BUT that means all of your relays must be switched to ground (switch on the 85 side) and if any of those wires ground out the load will have power. I would recommend just grabbing a 12v light, a battery and a relay and just trying the different setups on a bench. It might give you more of a feel of what’s best for you.

[@LetsGoBrandon_]

Pretty cool setup and demo. I've worked with HDPE welding and fab for past 30yrs but it looks like ABS is more popular for these projects so I'm switching materials to support some of the off-road community. Thanks for all your info here.

[@Sanjuro2112]

Best explanation of relays I’ve ever heard.

[@tehdreamer]

Bought a similar box for LED light bar, fog lights and rear lights. Although it feels like overkill for the LED lights, I might add more stuff later and it will look cleaner. Thanks for the vid!

[@Ghostrider304]

This video is perfect. I’m trying to clean up the wiring from 3 set of light I have on my truck. Hate having three different sets of fused and relayed wiring harnesses under the hood. Thanks!

[@richardniblack6408]

good rundown... I know a lot of my offroad buddies and I like to run the grounds through the switches and the relays instead of the hot as it makes for a lot less "hot wires" running through the vehicle meaning less likely to short out on a grounded surface. That way if the wire does get damaged and shorts the only downside is the component turns on as if you had activated the switch. Kind of like a horn or a dome light on most vehicles uses the ground as a trigger.

[@CodyWeilenman-yb5vk]

I agree with what youre saying but its not just a matter of the load activating, if you have a high amperage load and get a small short to ground, the heat created at that point would be problematic. And theres not much you could do as far as fusing that so youre kinda sol.

[@seancaron3323]

I love when a video is exactly what I was trying to find lol awesome video thank you!

[@MattsGarage]

Thanks Sean!

[@glockmaestro]

Great video!! Thank you

[@dirtyreddgray8275]

Nice and clean

[@achimwieler5862]

Great explanation 👍

[@nicholaskoenig3106]

Good work! Man this helps a LOT, and Ive watched 15 of these....took notes. Thanks so much!!

[@MattsGarage]

Thanks Nick!

[@Donder1337]

This was really helpfull!

[@dankcoyote]

This is great, thanks!

[@chriscynefin966]

The santa vs. political thing was SO WELL DONE for explaining 87(a). Thank you!

[@MattsGarage]

Thanks Chris, glad it resonated!

[@gazeddy]

the pin numbers on "bosch" relays are according to Din 72552

[@zigzag5145]

How to you plan on mounting this? Also what is the height of the dowls your using to raise the relay box from the mounting portion? Great video!!!

[@MattsGarage]

I still haven’t actually properly mounted it yet. It works great but still need to mount it permanently. I believe the standoffs were 3/4” but I got rid of them. It was a pain.

[@tankjohnson5242]

I do have a question about this as I am doing this same box to run my kc lights,led lights,air compressor..my question is 85 and 86 I see you wired 86 on some as the ground and others 85 does it matter witch one I run as the ground??I will also be running the rough country 8 gang switch panel and have live switch feeds..

[@MattsGarage]

You can put the switch either on the 86 side or 85 side. I don’t remember sending ground to 86 but it “should” be 85 to ground. However, I don’t think the relay cares about that either.

[@michaelfrymus]

I bought the kit you have in the video, but its pre-wired... It states its a 40A relay box, with 6 relays. Each relay is rated for 40A, and the biggest fuse is for 30A. BUT, I think I made the wrong purchase? I will have multiple devices that will have about 150A total, a max of 30A for a single device, most are only 3-7A.

[@laurencevillegarage]

I am working with a fuse/relay box that looks like yours. Mine came with green silicone wire plugs that go in the bottom to make the case moisture proof. Do you use them or are you mounting it in a place that does not matter?

[@MattsGarage]

I mounted them inside so I didn’t bother. Unless you are fording water it’s not necessary

[@chriscynefin966]

If you get a sec, what gauge of wire did you use for the battery terminal connection? Looks like 14...?

[@MattsGarage]

I'm pretty sure I used a 10.

[@billycooper1302]

what amp terminal block do you recommend using

[@MattsGarage]

Depends on what you are running. There is not 1 correct answer.

[@a.lumberjack4456]

Does 87a need to be wired, or skipped if not needed?

[@miguelrios6335]

Can u use a separate fuse box to send main power instead of a distribution block

[@MattsGarage]

If I’m understanding your question, yes.

[@miguelrios6335]

@@MattsGarage 10-4 just trying to figure out how to wire all my accessories I have the same box as in video and in the past bought a regular fuse box like a 12 channel wanted to run power to fuse box then from there run to relays I understand it would have 2 fuses would that affect anything

[@mileswatkins6472]

I have a short in a relay in the wiring how would I test to see where my draw is ?

[@MattsGarage]

Is the short in the relay or the wiring? With the car turned off you'd put your multimeter on the wires coming to and from the relay one by one and put the other probe on a good chassis ground or the negative baterry terminal. Obviously not the ground wire as that one would have continuity by design. You could use the continuity setting or ohms. If there is any continuity, or if the ohms are low, then that's your short.

[@mileswatkins6472]

@Matt's Garage big thank you for the reply and video

[@Blazin1978]

I couldn't get my 10 gauge wire to look in place due to the size. Did you have any problems?

[@MattsGarage]

What kind of wire are you using? I didn't have an issue but I use GXL wire which has thinner insulation.

[@yasser.busaleh]

im gonna install LED bar, camera with smart rear view mirror, and reverse sensors. Do I need to connect them to relays or only fuses are enough?

[@MattsGarage]

It really depends on the amp draw. Switches and fuses will work, but then your putting a lot of amperage through the switch. The relay avoids that as there is very low amperage required to trigger the relay. It's like the trigger on a mouse trap. A little force unleashes a bigger force.

[@yasser.busaleh]

@@MattsGarage i calculated a total of a bit less than 40 amps for all accessories. what do you recommend?

[@MattsGarage]

@@yasser.busaleh I’m not the right person to ask. I put a relay on everything more than 8 amps but you could probably go up to 15 per circuit. your LED light bar is the biggest draw right? You should put relays for the biggest draws.

[@zackfishle1009]

[cat reading news paper] I need a lightup sufing santa now [/cat reading newspaper]

[@angustinker2742]

I'll give u a sub to help out, great video mate

[@user-nh6fb9wm5b]

If a specific relay is no longer made for a car can you replace that relay using this method?

[@MattsGarage]

Theoretically, yes. They all do bascially the same thing. You just have to know/pay attention to the way it's pinned/wired. If it's just one relay you can just buy a single relay holder as well, probably easier.

[@user-nh6fb9wm5b]

@@MattsGarage Thanks

[@AnthonyExsted]

Ope, walp. I spose.