Vehicle Electrical Systems – Switch Install Tips

One of the most popular accessories to install on any four-wheel-drive vehicle is lights. It’s also one of the most popular upgrades as well. In prior articles I went over why I was choosing LED lights and a break down of installing new LED Headlights and LED Fog Lights on my Jeep. This time around I am going to give you some tips and tricks on how to control those lights.

Most reputable aftermarket light kits will come with some sort of wiring harness. This usually includes a fused power wire, ground, relay, and a switch. All you need to do is mount the switch somewhere easily accessible, tap into the battery, zip-tie the mess out of the way, and *BOOM* you’re done. That easy. Or is it?

The problem with most kit wiring harnesses is they are “one size fits most.” In some instances they are too long and in others too short. The other problem with most kit harnesses is the switches are rather boring. With that in mind, and with the recommendation of a friend, I checked out OTRATTW’s website and found some switches I liked.

Tip #1 – Future-proof yourself and leave room for growth

When I started this re-wiring project I only had one set of auxiliary lights installed on the front of my Jeep. They were the Rigid Industries High/Low D-Series lights installed in place of my OEM fog lights. Sadly the OEM fog-light switch on my LJ was shot so I had to wire them in using the included wiring harness. No big deal. When the LS swap was started that wiring harness and associated switch was removed. Now was a good time to not only rewire the lights but also install a better switch. It was also a great time to install a set of lights that were collecting dust on my shelf; a set of Rigid Industries Side-Shooters that would be mounted on the windshield hinges.

On the OTRATTW website I found a switch I liked for the fog lights as well as one for the a-pillar lights. I also know that at some point I’d like to install a pair of driving lights on the bumper as well as a set of “rock lights” under the Jeep for use around camp. Rather than go through this whole wiring mess twice I opted to get all four switches now and wiring all of them up once and then just add the other lights when I get them. This would prevent needless reworking later as well as making sure everything was accounted for sooner rather than later.

One reason I opted to install all four switches now is because of the really cool switch bezels as well as the location I would be installing them… which brings me to my next tip.

Tip #2 – Put switches in an easy to reach and easy to use place

Just because a switch is easy to use doesn’t mean it’s in a great location. And just because the switch is easy to reach doesn’t mean it’s easy to use. What I mean by that is think about not only where the switch is going but which had you’ll be using when you throw it. If using a lighted switch you want to make sure it’s not going to be somewhere distracting. If it’s a switch with text or an image you’ll want to make sure you can easily see it.

For me the best location for switches was on the knee-panel under the steering wheel. I can very easily drop a hand off the steering wheel to where the switches would be. For switches that would be “throw once and forget” like my fog light switches I opted to put them on the left side. For switches I may have to turn off and on multiple times, like my a-pillar lights, I opted to put them on the right. My reason for this is that the location of the OEM Headlight switch is on the left. It is very easy for me to flick back and forth between low beams and high beams without having to let go of the steering wheel. This leaves my right hand free to reach down and hit the a-pillar light if I have them turned on while on the trail and someone is coming toward me. I can hit both switches at the same time and still not let go of the wheel.

Tip #3 – Relays are your friend

Because the Rigid Industries High/Low D-Series lights have a built in attenuation down to 20% power I wanted to wire them in sequence with my headlights. That way I could switch back and forth between high beam and low beam on the fog lights using the OEM headlight switch. In order to do this without the ease of a standalone electrical management system like an sPod or Switch-Pros it meant we had to get old-school: relays.

With a trio of relays we were able to have one relay control the on/off function of the fog lights using the dash mounted switch. The second relay would then control the low beam function and the third the high beam. Before any Radio Shack guru’s jump on me, yes I know there are easier ways of doing it but for now this works and it used existing relays we had one hand. The point is relays can help you “automate” some light functions and use existing switches and add some functionality to your lights you may not otherwise have using a single switch and single relay combination.

Tip #4 – Use quality components

I love Rigid Industries lights but to be honest their wiring and switches leave a little to be desired. Quality? Sure. Functional? Sure. Safe? Sure. But those little red switches are boring and they are the cheapest part of an otherwise good harness. In contrast the OTRATTW switches are a high quality switch with a nice finish and great functionality. They also have multiple options for text, icon, and lighting options. They aren’t cheap, but you get what you pay for.

What I do like about the Rigid Industries wiring harnesses is their use of Deutsch connectors. They are a high quality weather tight plug that has become the gold standard (as far as I’m concerned) when it comes to electrical connections. Duetsch connectors are a much higher quality connecter than most of the other plastic connectors out there and far exceed most OEM wiring connectors. With that in mind we opted to use Duetsch connectors when wiring up the switches in the dash.

Wiring connections is a great reason to remember why Rule #1 is rule number 1. For me I’d have four switches each needing power, ground, lighting, and an outgoing signal. To complicate matters I also have two LED dimmer controllers mounted in the same vicinity of these switches which also need their own power and ground and each have an outgoing signal wire. When you start doing the math that’s a lot of wirings. Luckily Duetsch connectors come in sizes ranging from 2-wires all the way up to 48-wires.

Tip #5 – Batch wires when and where you can

It would be a nightmare if I tried to wire every switch independently with its own dedicated power, ground, light, and signal wire. The switches I got from OTRATTW require five wires. That’d be 20 wires. Plus another 6 for the dash dimmer controllers. That’s 26 total wires. Not fun at all. However, by batching wires together we can often “jump” or “chain” multiple similar wires together.

Because relays don’t need a whole lot of power to actuate there is no reason you can’t jump power and ground from one switch to another. Because LED’s don’t draw much power you can also do the same thing with the power and ground for the indicator lights in the switches. This really simplifies things. So let’s do some more math and see if we can drop from 26 wires down to something more management.

We know we’re going to have six outgoing signal wires (1 from each switch = 4; 1 from each dimmer = 2). We can lump all the switches together for power, ground, and lighting which gives us three more. We’re at a total of 9 right now. That just leaves a power and ground for the two dimmers which can chained together. That leaves us with 11 total wires. That’s a lot more manageable – compared to 26 at least.

Tip #6 – Discipline with wire connections

This is probably the absolute most important thing when it comes to vehicle wiring. The vast majority of vehicle fires are started because of some sort of electrical short. Could be a bad component, could be chaffed wire insulation, but more often than not it’s a bad connection.

This is also a “do as I say, not as I do” thing. I’m going to admit that I am notoriously bad at using those blue crimp-on wire tap connectors. My friend cringe at them. I cringe at them. Now I’m trying to remove as many as I can from my Jeep before something bad happens.

This is why good twisted wire, soldering connections, and using heat-shrink is time well spent. Yes it’s more of a hassle. Yes you have to take the time to do it right. It’s worth it. Trust me, it’s worth it. This also means that – Tip #4 – you’re using good wire, good solder, and good heat shrink. Using a blue crimp on tap and wrapping it with duck tape is not good wiring – I know and I admit to having done it way more than I should. I was a bad boy. Moving on.

So what does this look like in practice (photo dump)

Left switch bezel installed – right one traced out and ready to cut.
Both are cut out and now it’s time to flip it over and work on the backside.
Wires have been twisted together and prepped for solder
Note: make sure the heat-shrink tubing is on before you connectors the wires.
Here you can see how the ground (black), power (red), and illumination (white) wires have all be jumped between the two switches.
You can also see how all the of wires have been batched together and run at one bundle rather than a half dozen separate wires.
Another example of how everything was batched together and secured behind the knee panel.
You can also see how excess wire was left via the spools so the harness pig-tail could be made as long as it needed to be.
Here is the finished Deutsch connector (pin side) all finished.
Again, notice how everything is batched together into one single plug rather than a half dozen separate wiring harnesses.
Here is the (almost) finished socket side of the Deutsch connector.
This is another good area to batch and jump wires when able.
Fog & Driving lights mounted on the left side of the steering wheel.
They are “flip once and forget” switches for me since they will run in sequence with my headlights when engaged.


A lot of people are intimidated by wiring up aftermarket accessories. However, with a little discipline, the right quality components, and taking the time to plan everything out you can end up with a very nice clean install when all is said and done. Hopefully this helps you get started on your next wiring project.

I would like to give a huge shoutout to Alex (@echo_alex) for his help wit this wiring job. I can do wiring and make it work. Alex can do wiring, make it work, make it look good, and more importantly make it safe. I am super grateful for his skills soldering the innumerable wire connections and wiring up the Deutsch connectors. So if all else fails, and you’re not sure you want to tackle your wiring project on your own, it never hurts to call in reinforcements for help!