Keep Your Car Safe With a Kill Switch

No one wants to find their vehicle missing because a thief stole it while you’re away. Older models are at higher risk because they lack the antitheft devices we take for granted today. While most vehicles employ multiple security devices, it never hurts to add one or two of your own.

A kill switch can help protect your vehicle from car thieves. It prevents most thieves from driving off with your car. There are several types of kill switches available, so you can choose the one that fits your unique application.

What Does a Kill Switch Look Like?

A kill switch is a hidden switch that stops the engine from starting. It prevents thieves from driving off with your vehicle if they manage to break into its interior. This security device is usually located somewhere it won’t stand out to hide it from unwanted attention.

You can usually combine different kill switch types for increased protection. Even if one of the kill switches gets identified and defeated, car thieves still have to deal with the other security measures.

Types of Kill Switches

Below are the types of kill switches that help prevent car thieves from getting away with your vehicle:

Starter Disable Kill Switch

If you clip the wire that energizes the starter solenoid and put a simple hidden toggle switch somewhere easy to reach but hard to see, it’ll be very difficult for a thief to start the car.

Fuel System Relay Kill Switch

The fuel system relay kill switch disables the engine’s fuel supply. They’re small, easily installed, and easy to hide and use.

Most fuel system relay kill switches are on/off toggles in the positive circuit of the fuel part. You can hide the switch in any location. However, you must connect the switch to the electrical wiring. Recommended locations include under one of the seats, inside the glovebox, beneath the dashboard, and in the trunk.

Some fuel kill switches disable the fuel pump that transports gasoline or diesel to the engine. Others turn off the fuel injection system that sprays the fuel in the cylinder. Their methods differ, but the result is the same.

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: If you have a perfectly restored ‘60s or ‘70s muscle car with a carburetor, you’ll need to get a solenoid valve to close off the fuel supply from the tank and it needs to be in a place where the thief won’t have time to look.

Battery Disconnect Kill Switch

The battery disconnect kill switch cuts off electrical power from the car battery, de-energizing your vehicle. While more complex than its fuel system relay counterpart, this type also immobilizes your vehicle more thoroughly.

When set in the off position, the kill switch disconnects the car battery’s circuit. It de-energizes your vehicle, turning off electrical devices that run on battery power. One of the affected parts is the ignition system that starts the vehicle.

Unfortunately, the battery disconnect kill switch also resets electronics that draw power from the car battery when the engine isn’t running. Devices like the clock and radio might reset to factory baseline and clear their memory. You’ll have to reenter the correct settings.

But here’s a solution to that problem:

There are heavy duty relays that can be used for this, and they can be wired to interrupt the main battery wire where it goes to the starter. The only problem with this is that some cars use the main starter post as a junction and have fusible links feeding other things connected to it, so you may kill the other things.

If, however, you mount the heavy duty relay close enough to the starter, you can transfer the fusible links with their lugs to the large always hot battery hot post on the heavy duty relay.

You can install the battery disconnect kill switch on the positive battery cable. In many setups, the kill switch goes under the hood. Alternatively, extend the positive battery cable until it reaches the driver’s seat, where you can install the switch. If you extend the cable, use a 0-gauge cable and a heavy-duty rotary switch.

The battery disconnect kill switch also resets electronics that draw power from the car battery (like clock and radio) when the engine isn’t running. But there are heavy duty relays that can be used for this, and they can be wired to interrupt the main battery wire where it goes to the starter. The only problem with this is that some cars use the main starter post as a junction and have fusible links feeding other things connected to it, so you may kill the other things.

– Richard McCuistian, ASE Certified Master Automobile Technician

Ignition Wire Kill Switch

The ignition wire kill switch disables the ignition system. Putting the kill switch in the “off” position cuts the connection between the ignition switch and the starter motor that cranks the engine. It stops the activation signal from the ignition switch from reaching the starter, thus preventing cranking and starting.

Installing an ignition wire kill switch is a complex job. Your vehicle’s wiring diagram will come in handy here. Consult the diagram for the wire leading to the starter solenoid that controls the starter motor. You must put the kill switch on the electrical circuit as far from the ignition system as possible to ensure it stays hidden.

Fuse Box Kill Switch

Do you want the benefits of a kill switch without the time-intensive labor of installing new wiring and parts? The fuse box kill switch leverages the vehicle’s existing fuse box to prevent your car from starting without your permission.

Fuses protect the electrical system from overloading. If a current with excessively high voltage passes through a fuse, the device blows, cutting the connection.

The fuse box kill switch replicates the effect of a blown fuse by disabling or removing the fuse that protects the wiring from the battery or the wires leading to the fuel or ignition system. It hides in plain sight by pretending to be a part of the fuse box.

Remote Car Battery Kill Switch

The remote car battery kill switch lets you disable the vehicle’s battery power from a distance. It’s usually part of the key fob. With the press of a button, the remote car battery kill switch will wirelessly cut off power from the car battery.

Pull the Fuel Pump Relay

Instead of installing a kill switch, you can remove the fuel pump relay from the main fuse box. This relay is the electromagnetic switch that controls the current flow to the fuel pump. Removing it deprives the fuel pump of power.

Modern vehicles keep their fuel pump relay in a relay block. You can find the relay block in either the engine compartment or under the rear seat.

Installing a Kill Switch

Keep a complete wiring diagram of your vehicle at the ready before installing a kill switch. The diagram will help you locate and identify the wires you need to modify.

Where to Find a Kill Switch for Your Vehicle

Your vehicle can only do so much to keep itself safe from thieves. Crooks have gotten craftier over the years, so simple anti-theft devices aren’t as effective as they were before. Luckily, there are still some things you can do to improve vehicle security, such as installing a kill switch.

Here at CarParts.com, we are dedicated to giving customers like you only the best parts for your ride. We have high-quality kill switches carefully handpicked by the most trusted industry professionals, so you can rest assured that our products are built to last.

Start shopping for a high-quality kill switch by entering your daily driver’s details into our vehicle selector. For a more personalized shopping experience, use the search filters to find products according to your preferred brand, price range, quantity, and more.

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