Who doesn’t love a simple DIY car modification? It’s made even better in this case because the result is the potential to save your car from a criminal. Adding a killswitch is a simple project that even someone with virtually no mechanical experience can tackle. Best of all, it’s extremely inexpensive.

Shutting down a key ingredient for your engine makes it impossible to drive

A gasoline engine needs three things to run: fuel, air, and spark. So, shutting down one of these three elements will prevent your car from running. This is possible by way of a killswitch in line with either your fuel or ignition components. While it is possible to cut off a distributor or ignition coils with a killswitch, the simplest way to install one is on your car’s fuel system—specifically, the wiring to the fuel pump.

ChrisFix put together a fantastic killswitch install video in which you can see just how quick and easy it is to install. Best of all, a killswitch can prevent your vehicle from being stolen even if the thieves have your key, break the ignition barrel, or even hotwire the car.

The fuel pump cut killswitch is the most straightforward install because it only requires the modification of one wire. Because of this, the parts needed to do this installation are extremely affordable. You only need a 25 amp switch available at most auto parts stores or DIY supply stores for less than $10 and some basic crimp-on wiring terminals.

Effectively, you are putting the killswitch inline with the wire that powers your fuel pump relay. So, all you need to do is add the switch to this one wire. Additionally, you can add as much wire as needed, so you can place the killswitch anywhere in the car and only share that information with trusted individuals.

Locating your fuel pump relay

The location of your fuel pump relay varies from car to car. Often, a quick google search will net you the results. Additionally, wiring diagrams are also typically readily available online and in repair manuals.

Once you’ve located the fuel pump relay, it’s as simple as identifying which pin is the switched 12-volt power to the relay when the key is turned on. The relay will have a constant 12-volt supply, too. In theory, interrupting the continuous hot wire would net the same result.

Before you cut any wires, be sure to unplug your car’s battery to ensure there’s no risk of shocking yourself or blowing any fuses.

Once you’ve identified your wire and removed the battery power, it’s as simple as cutting the wire with enough room to strip it and crimp or solder it. Then, all you have to do is wire the switch inline with the cut wire. Using things like spade connectors makes the switch easily removable if you install it in a piece of paneling like Chrisfix demonstrates in the video.

Ultimately, the only thing you’ll need to decide is where you want to put the switch. Get creative! While the glovebox may seem like a good idea initially, that’s the first place many criminals will look when it comes to stealing a car. Under the dash near the steering column is also relatively common. So, a bit more ingenuity will make your vehicle more difficult to steal.

Overall, this is an excellent simple DIY install that just about anyone can do. It’s cheap and could very well save your car from being stolen!