DIY Relay Panel & Light Wiring Writeup -
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post #1 of 4 Old 07-11-2019, 09:34 PM Thread Starter
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DIY Relay Panel & Light Wiring Writeup

Howdy boys and girls,

I just finished a huge revamp of the auxiliary lighting system in my JKU and for once I actually took enough photos to do an in-depth writeup!

4 years ago I rushed to wire up a cheap 50" light bar for a trip to the San Juan mountain range in Colorado. I don't have any pictures of the wiring from then because I knew it was garbage so here's a picture of just the installed lights

Anyways, about 2-3 years later I finally decided enough was enough of my ****ty lightbar that had an awful whistle whenever I was going highway speeds so I purchased 4 Baja Designs XL80's which were stupid expensive but within my budget after saving for a year

And let me tell you these bad boys were absolutely life changing. I was always skeptical of the brightness difference between name brand lights and cheapo lights but after seeing these powered up I was convinced. The lights shipped with a harness from factory that had measly 18 gauge wire but I was already so blown away by the improvement I didn't think twice to change it out.

FAST FORWARD to two years later in the summer of 2019, I'm on break from my professional school program and have found myself incredibly bored, looking for projects to keep myself entertained. I put together a list of projects I wanted to get done and "Fix JKU Wire Rats Nest" was finally next

Let me clarify that I am not proud of this wiring and that's why there has never before (until now) been proof available anywhere online, but I needed a before picture to really appreciate the after.

To accomplish this goal I needed a clean, safe and secure way to arrange relays/fuses/wiring that could power my current and future planned lights in addition to constructing a custom wiring loom to send power to each light pair. In addition to this, I was going to be running a third wire to make use of my lights "dimming" feature (from 100% to 20%). First I had to remove all of the existing garbage:

Here's the rats nest one more time to spook you

Once the existing wires were removed, it was finally time for me to start on the project which had two prongs. I needed to 1. Make a relay/fuse panel that would be able to handle and distribute all of the power for my lights and accessories then 2. Construct a wire loom with the appropriate gauge wire to actually power the four lights. During the past 3-5 days I really alternated between these two facets but I'll first talk about the wiring loom and save the relay panel for last. To plan out these projects, I started first with a wiring diagram for the wires and a second for the interior switches and fuse panel. Do note that the drawing for the fuse panel was just for the V1 prototype. I did not make a diagram for the V2 panel that will be attached later.

These diagrams were absolutely priceless during my build and I 100% recommend anyone draw up plans before starting any wiring endeavor whatsoever.

Anyways onto the wire loom. First I needed to decide how exactly I wanted to arrange the harnesses coming from the lights. Previously I had the wires ziptied to the roof rack in a manner that would prevent the rack from folding back and although I have a hardtop, something I really wanted to ensure was that I could retain the ability to flip my rack back even though I have absolutely no plans to every while my JKU is still standing. I found that wrapping the factory harness from the lights around the base of the light was a very nice way to "manage" the 1.5' harness to make a wire loom easier to build.

(In that picture the harnesses are all pointed to the passenger side, but in the end I had each pair pointing towards the other)

Once I had a mental picture of the loom I needed to construct in addition to the wire lengths I calculated out in my diagram, I started cutting, splicing and heat shrinking.

I needed to minimize the bundle of wire I was going to pass down so I had to reduce the wires from 6/pair to 3/pair by using a smaller 16 gauge running from the lights that would be spliced together into the master 12 gauge. The main reason I did this was because it would make absolutely no difference in the end result, and because I needed wires small enough to crimp into a naked connector that I could then heat shrink

Once all of my splices were done per pair, I did a layer of heat shrink over them to insulate. I removed all of the plastic shells from my crimp connectors to reduce overall size in addition to improving the overall look of the build. The ****ty 18G wires from factory used naked connectors/heat shrink so I know my 12G wires with heat shrink will do fantastic.

Once the antennae's containing the wire going to my lights were finished, I used an additional piece of heat shrink to hold all of the wires together in a neat aesthetically pleasing package.

Here's a closeup for some reason of the joint between the 3 different wires

Fast forward a day and the loom is done! once the wires were done and heatshrunk to be the exact length needed, I used some stupid beefy heat shrink to finish protecting the wire bundles

Once my loom was done, It was time to actually install it.

Now that the loom was done, it was time to start using the fancy-shmancy factory connectors baja sent me. To utilize these I had to first be certain to the wire order for each pair (From ground, hot, dim) so that I could arrange the wires in MY loom before crimping the connector pins on.

Once the connectors were installed, It was time to install the loom.

The hardest thing for me to do while routing this loom was passing the bundle through the trim under the wipers because I had to bend it (using towel wrapped pliers) ever so slightly however it was truly the best way I could pass the wire through with minimal risk of the wire being worn down and shorting out/blowing a fuse.

Once everything was wired up I could not have been happier with the end result. I knew from the start I did not want to run the wires inside the cab and I only wanted to run them down the roof rack bar into the engine bay. Additionally I wanted to minimize visible wire as much as possible and have the final product look as professional as it could. Given these limitations I could not be more satisfied with the end result. I would estimate that the thicker gauge wire netted 20-30% more brightness and I cannot WAIT to see them offroad.

Given the current time, I'll probably wait to post about the relay panel tomorrow but I will leave a teaser of the V1 panel.

DO NOTE: I am aware of all the issues present on this panel, as it was mainly a prototype to see what I wanted the final product to be so I recommend saving any criticisms for the V2 panel I'll post tomorrow

EDIT: Um, okay why are my photo links from imgur not working?

EDIT 2: Well I have no idea why my imgur links aren't working. I've used them in the past so I suppose for now just ignore this post. Once I figure out the issue I'll post part 2 (which is the really juicy part anyways)

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post #2 of 4 Old 07-11-2019, 10:18 PM Thread Starter
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Well apparently JeepForum is super touchy about the type of markup used, but there they are!

EDIT: I'm editing because I don't like numerous useless posts, but if anyone sees this comment the format you must use from imgur is:

VS what JF tries to insert image links as:


Replacing { with [ obviously

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post #3 of 4 Old 07-12-2019, 01:39 PM Thread Starter
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Okay time for part 2. I'll begin by reposting the image of the relay panel planned out:

First, I needed to find a material to serve as the base for my panel. I cut a 9"x9" fiberboard and coated it in fiberglass resin for waterproofing and stability. At the time I was hoping the resin would completely penetrate the fibers and 100% waterproof the material but unfortunately I realized while drilling this was not the case. I have already sourced a material to transfer the components onto and will use the existing board as a stencil to drill holes in the exact same positions:

The connectors on the old relay had started to melt due to heat. I believe this was due to the factory wiring harness being a puny 18G but I decided anyways to just forgo the connectors in favor of insulated female pin connectors:

Once I had a rough mental image of the route I wanted to take, I started to play around with the positioning of my wiring components until I finally had a setup I liked. I then used some 1/0 CCA garbage I had leftover from a subwoofer install to make master wires to connect to my battery terminals. I'll be replacing these with pure copper welding wire eventually:

Once I had made some progress on the relay panel, I decided it was time to update the switches in my cab. the Red switch you'll see is what I used to power my lights for the past 4 years DESPITE having the "OTRATTW rocker switch" that I specifically ordered (Notice that it is titled LED Light Bars because I bought it when I still had bars) but for some reason 4 years ago, I could not find a way to tap into the interior lights/dimmer circuit so that was all it took for me to not want to install it. By now I have gotten much better at doing research and I was able to find a wire in the window switch harness that would provide me with the signal I was looking for. Also notice the tiny toggle switch installed that controls the dimming feature on my lights from 100% to 20%, although it visually looks closer to 100% -> 60%:

(This is from a screenshot in an online video, but that circled orange wire is where I used the previously pictured blue splice connector. I then ran the wire behind the dash and to my A-pillar switches. It was incredibly easy)

By this time my board was at a phase I'll call V1. I knew it was a great prototype but it was never intended to be my final version. In the next image I highlight the issues I personally had with the V1 board and used these to make most of the changes in the V2 board:

On panel version 2, I added 3 more relays so that when I add my Left/Right perimeter and reverse lights I'll already have the relays in place. Additionally I added the cinch blocks to facilitate the connecting and disconnecting of my lights & accessories. More importantly, I think it made it much easier to "clean-up" the wiring on the panel and create a much more professional product. During the process of actually installing the panel my thoughts were correct as I was incredibly satisfied with how everything went in:

All wires are 12AWG
RED = Fused 12VDC
BLACK= Ground
BROWN= Incoming signal from switch
WHITE= Relay-->Lights power signal

(Note that the last image shows me testing the panels wiring to be certain everything was correct with no parasitic drains or anything)

Once I knew my panel was solid, it was time to run the new circuit to my high-beams that would allow me to control the spotlights with them. To do this I spliced a wire into the white/grey high-beam wire in my headlight harness. Testing this pin with my meter shows that the circuit gets 2V of power when the low-beams are on and then 12V when the high-beams are on which is exactly what I needed for my relays. With the engine off this circuit functions absolutely perfectly and before anyone tries to criticize the spotlights coming on whenever my high-beams are on allow me to explain my reasoning. The only time I use my high-beams is in the dead of the night when there are no other cars or when I'm off-road. In Texas, you are allowed to have two additional auxiliary driving lights. And yes this circuit does control four auxiliary lights but the way I've designed it I can easily add a diode into my switch wire that will allow the switch to control four lights and my high-beams to control just the two that are legally allowed albeit not at all enforced:

(I have included this picture again to bring attention to the high-beam trigger circuit from the blue wire with the super thick bundle of yellow heat shrink covering the diode to prevent electricity backflow into my high-beam from the switch. In hindsight I don't think the switch uses enough electricity to actually cause the beam to activate but I did it anyways)

By this time despite my lights functioning flawlessly either through the switch or the high-beams, the "upper dependent" LED that should be lighting up my graphic when the lights were on was always illuminated. I realized that I mistakenly flipped the two pin connections as indicated in the following picture. Afterwards the switches lights functioned as intended:

One the loom was done, the panel was properly sending out power and my switches/high-beams were functioning as intended I considered the project a complete success:

EXCEPT one tiny hiccup. Many of you may know that when retrofitting the halogen factory lights, you need an LED anti-flicker harness for your new lights. Well it's been a while and as such I forgot that the JKU's headlight circuit did not have a steady current flow for some inexplicable reason, so while the engine is running the spotlights triggered via high-beam to have an obnoxious flicker. To remedy this I will be adding a 6800uF capacitor into the high-beam trigger circuit. I will likely put it behind the diode so that it doesn't waste effort trying to even out the signal from the switch (that doesn't need it) and then I'll run the other wire from it to my grounding bus bar

With that being said it is not at all complete because I still need to add that 6800uF capacitor to the high-beam trigger-circuit, better manage the wires in the engine bay, swap the 150A CB for a 100A CB, transfer all components onto a more suitable base material and install the assembly into some sort of weather resistant box. Despite all electronics being sealed/weather resistant (except some possibly not sealed relays) I would like to treat the components with tender care and love to show them how special they are to me. I have absolutely no idea what I will put them into just yet because no project box fits my panel's dimension, so I feel as though my V3 panel might need to have the components ever so slightly rearranged. Unfortunately this means all of my beautiful cable management would go to waste, but on the bright side I know the final cable management would be superior to that of my V2 panel. I've never routed wires before and the order I routed these was Red>Black>Brown>White. It might just be because I know, but looking at the wires I can tell I got better and better by the end of the white wires

Now onto some closing thoughts.
Some of you might say:
"You could have bought XYZ that would be much more simple and do everything you wanted this panel to do"
To which my response is no, no commercially available & affordable panel would be able to do what I'm looking for. My master plan is to have each of my lights on a low-voltage cutoff circuit that will automatically cut them off before my battery loses enough charge to crank the engine. Additionally I will be connecting my interior switch panel to a 7-pin trailer socket that will be installed into my hardtop near the back somewhere. I'll then have a second switch box that I can plug into said socket and keep inside my roof top tent so that I can control all of my lights from the tent whenever I'm camping. True I might have been able to adapt a commercially available product to fit these needs but in the end it would have been much more difficult for me to wire this into someone else product vs one I built myself. Honestly I also just really enjoy stuff like this so wiring my own panel was a lot of fun.

"You shouldn't have your high-beams trigger your spotlights, that's not safe"
Which I'll repeat the ONLY time I use my high-beams is in a scenario where my spotlights would be deemed "safe"

"This looks like a lot of work, I would much rather just buy something"
Yes, it was a lot of work and took me about 3 days to finish, but in the end (not counting components I had on hand) it cost about $70 to build. In addition, having my own custom panel that I know from top to bottom is absolutely priceless as far as future modifications, changes and upgrades. There's only so much you can do when you buy something like this

"That looks like a fire hazard"
If you don't know how to work with wiring or electricity then I 100% DO NOT recommend doing something like this yourself. Luckily for me I was exposed to electrician work from a very young age and as such I have absolute confidence that this poses no more fire risk than my engine block spontaneously combusting in the middle of the night

"Tapping into the high-beam or interior dimmer sounds like a great way to fry your CAN bus"
If you aren't careful with your wiring, anything can be an easy way to fry electronics in your Jeep. The two factory wires I've tapped into are the window dimmer wire and the high-beam wire. Both of these will not experience enough of a current draw to even be detected by the vehicles computer

Anyways this has been my wiring/DIY fuse panel writeup. If anyone has any further questions, would like specific pictures or measurements please feel free to ask! As I make changes, add new lights etc I plan to update this thread accordingly

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post #4 of 4 Old 07-12-2019, 02:08 PM Thread Starter
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Here are some short clips showing the lights in action. I do not believe JF has the capacity to display GIFs, so I'll have to link to them.

Low beam headlights >XL80ís 100%

XL80ís 100%>20%>100%>low-beams

Old video of the XL80ís with wiring harnesses a friend filmed while I was testing them.
I will need to check the lights out somewhere more open to get a better idea of just how much brighter they are, but I can safely say from being up close they are at least 20-30% brighter

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