Installing a Kill Switch in the Jeep Wrangler

Make your Jeep much harder to steal, even if the thief has the key.

The Jeep Wrangler is one of the most easily-recognizable vehicles sold in the United States while also being one of the bestselling SUVs in the segment. The problem with that familiarity and popularity is that the Wrangler can become the target of a thief, especially when the vehicle has been modified.

The key fob system on pretty much every modern vehicle makes the Jeep Wrangler harder to steal, but a simple kill switch makes the vehicle impossible to steal without a tow truck. Today, we bring you a look at a great do-it-yourself thread written up by “Grecy”, who showed how easily you can install a kill switch for about $15.

The Introduction

When the OP first introduced the forum to his kill switch DIY, he started by explaining the items needed for the install and the tools needed, along with a few key points to consider before attempting the installation.

A hidden kill switch is great theft deterrence – even if someone manages to get your keys, they still won’t be able to start the Jeep. It’s an easy DIY on the cheap, total time is something like 30 – 45 minutes.

Things to buy
– A small momentary switch like this: Momentary car push button switch for about $8.
– Some wire like this: 12ga 25′ Red/Black hookup wire for about $7

Tools needed
– A soldering iron and solder, or good quality wire crimps and crimper.
– Wire cutters / strippers.
– Electrical tape.
– A drill and drill bit to mount the switch someplace

Overview:

We’re going to use the Clutch Interlock Signal to stop the Jeep from starting unless a hidden switch is pressed. You can wire it so the switch AND the clutch must be pressed for the Jeep to start, or so that only the switch must be pressed. I personally chose to wire it so that only the switch must be pressed because I’m used to vehicles that don’t have clutch interlocks – with it in neutral, and the e-brake on, obviously.

NOTE 1: Cruise control will no longer disengage when you press the clutch after doing this modification. If you regularly disengage cruise with the clutch (I never do), maybe you shouldn’t do this mod.

NOTE 2: The Jeep ignores the clutch interlock signal when in 4LOW. Therefore this kill switch will not function when the Jeep is in 4LOW. (We could modify the wiring on that relay too, I just don’t think it’s worthwhile)

He also included the simple image shown above of the switch that he used and the wiring. It should be noted that he did not include a picture of his switch mounted, as he didn’t want everyone on the internet to know how to start his Jeep. However, we found this picture of him and his Jeep in another thread and included that above.

The Install

Next, the OP walked us through the surprisingly simple installation process, explaining which wire in the engine bay of the Jeep Wrangler needs to be located and spliced-into. Take note of the fact that the OP is applying a kill switch to a vehicle with a manual transmission, so he is using the signal from the clutch to the PCM. When you start a manual vehicle, depressing the clutch works the clutch, but it also sends a signal to the PCM that the clutch is depressed, making it safe to start.

With this DIY, even when the clutch is depressed, the PCM will not receive that signal unless the kill switch is being pressed as well. Even if the thief has the key, the Wrangler will not start with this modification until the switch is being held down.

If your Wrangler has an automatic transmission, you can apply a similar kill switch system by splicing into the crank shaft position sensor, camshaft position sensor or starter signal wire, as is pointed out by “2climbbig” in the thread.

Also, while the OP chose a type of switch that only works while being pressed, some owners prefer a toggle switch that can be flipped to “on” to start all of the time, but when there is a concern of security issues, flipping the switch to “off” will prevent the Jeep from starting. The downside to that type of switch is that if you don’t remember to turn it off, the kill switch will not do its job, whereas a momentary switch like the one used by the OP is always active.

Of course, if someone really wants to steal your Jeep, almost nothing will stop a thief with a tow truck, but when it comes to preventing someone from driving away in your Wrangler, nothing works as well as a kill switch.

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Patrick Rall

"Before I was old enough to walk, my dad was taking me to various types of racing events, from local drag racing to the Daytona 500," says Patrick Rall, a lifetime automotive expert, diehard Dodge fan, and respected auto journalist for over 10 years. "He owned a repair shop and had a variety of performance cars when I was young, but by the time I was 16, he was ready to build me my first drag car – a 1983 Dodge Mirada that ran low 12s. I spent 10 years traveling around the country, racing with my dad by my side. While we live in different areas of the country, my dad still drag races at 80 years old in the car that he built when I was 16 while I race other vehicles, including my 2017 Dodge Challenger SRT Hellcat and my 1972 Dodge Demon 340.

"Although I went to college for accounting, my time in my dad’s shop growing up allowed me the knowledge to spend time working as a mechanic before getting my accounting degree, at which point I worked in the office of a dealership group. While I was working in the accounting world, I continued racing and taking pictures of cars at the track. Over time, I began showing off those pictures online and that led to my writing.

"Ten years ago, I left the accounting world to become a full-time automotive writer and I am living proof that if you love what you do, you will never “work” a day in your life," adds Rall, who has clocked in time as an auto mechanic, longtime drag racer and now automotive journalist who contributes to nearly a dozen popular auto websites dedicated to fellow enthusiasts.

"I love covering the automotive industry and everything involved with the job. I was fortunate to turn my love of the automotive world into a hobby that led to an exciting career, with my past of working as a mechanic and as an accountant in the automotive world provides me with a unique perspective of the industry.

"My experience drag racing for more than 20 years coupled with a newfound interest in road racing over the past decade allows me to push performance cars to their limit, while my role as a horse stable manager gives me vast experience towing and hauling with all of the newest trucks on the market today.

"Being based on Detroit," says Rall, "I never miss the North American International Auto Show, the Woodward Dream Cruise and Roadkill Nights, along with spending plenty of time raising hell on Detroit's Woodward Avenue with the best muscle car crowd in the world.

Rall can be contacted at QuickMirada@Yahoo.com

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