How to Wire a Fuel Pump to a Toggle Switch (Steps With Photos)

Wiring a vehicle’s fuel pump to a toggle switch will give you direct control and is an extra security strategy against attempted theft, but how do you do it?

Today, we have a guest writer, Rafael Lizarraga (Rafiki), a stereo and auto security installer for cars for the past 20 years, who has used this method a hundred times. Fortunately, wiring an electric fuel pump to a toggle switch is pretty straightforward.

In general, to wire a fuel pump to a toggle switch:

  • Locate your fuel pump components and wiring and gain access to them. Examine the power of your fuel pump.
  • Connect the fuel pump cutoff switch to the fuel pump.
  • Your fuel pump wire should be cut and spliced. Your kill switch protects your car wiring by cutting electricity to your pump when necessary.

I will go through them in detail below.

Why Install a Toggle Switch on the Fuel Pump

Direct Control

The fuel pump plays a pivotal role in the heart of a vehicle’s fuel system.

Its circuit is an engine’s veins, given that fuel is an essential vehicle element. Wiring a fuel pump to a toggle switch can give you direct control and a manual override. However, such modifications require detailed know-how, which this article gives, as well as safety concerns.

I will also give you a wiring diagram and tell you the required tools for the job.

Theft Prevention

There was a huge spike in car thefts last year.

They went from 721,885 to 810,400 thefts. Learning how to wire an electric fuel pump to a toggle switch is one of the most powerful strategies to deter automobile thieves. This simple system will shut down your electric fuel pump, making it impossible for someone to steal your automobile.

The toggle switch will function as a kill switch, which only you will know about.

What You Will Need

Tip: I highly recommend hiding the kill switch so that auto thieves won’t be able to steal your fuel pump.

Step 1: Locate and Access the Fuel Pump

A person wearing a blue gloves locating and accessing fuel pump
Video | ChrisFix

Find your vehicle’s electric fuel pump.

The fuel tank is the most likely spot. Loosen the filler cap from the fuel tank and place your ear near the nozzle. Make sure someone turns the ignition key from off to power. You should hear the gasoline pump click or buzz for two or three seconds after it turns on. If you’re certain the pump isn’t inside the tank, trace the fuel line from the tank to the engine until you find it.

Locate the fuel pump components and wiring and gain access to them.

Depending on your car, you may need to remove your back seat or reach the fuel pump through your trunk. It doesn’t matter how you reach the gasoline pump assembly. You’ll need to be able to get to the connector and then strip and cut the connections.

Step 2: Inspect Your Fuel Pump Power

You should check the fuel pump’s voltage using a digital multimeter.

Unplug the fuel pump harness and examine the switched current by grounding the multimeter’s black lead. Remember that you must have your ignition switched on for this to function.

A person wearing a blue gloves inspecting fuel power with multimeter
Video | ChrisFix

Check if you can route the cables to the outside of the car through the floor.

Drill a hole if necessary. Also, ensure an adequate area for the switch assembly and wiring under the switch.

Step 3: Install Your Fuel Pump Kill Switch

Install the switch in your desired spot.

To secure it in place, insert it from the back and tighten the ring nut on the switch’s body on the outer side. Ensure the on and off positions are correctly oriented, i.e., up is on and down is off.

This phase is simple if you’ve purchased a complete kill switch kit. You can connect your fuel pump kill switch using a common single post automotive relay by following the circuit diagram for the fuel pump kill switch shown below.

Toggle switch wiring diagram for a fuel pump
Video | ChrisFix

The above toggle switch wiring diagram for a fuel pump indicates how to modify any standard automobile relay.

When you’ve finished installing your kill switch, you can turn off your gasoline pump anytime. The gasoline pump kill switch can then be hidden or stashed so a thief cannot find it.

Step 4: Disconnect the Power Line to Your Fuel Pump

Using the above wiring diagram, trim and splice your fuel pump components.

Your single post relay and kill switch will safeguard your car’s wiring and shut the electrical connection to your pump on command.

Double-check your wiring after installing the fuel pump kill switch to ensure the pump does not turn off automatically.

A person wearing blue gloves holding two blue wires
Video | ChrisFix

Although fast electrical connectors can be used, I highly suggest you solder your connections.

Never access the fuel pump component when installing a gasoline pump kill switch. Gas vapors or fumes can create a hazardous working environment.

Useful Tips

When performing this anti-theft strategy, keep a few crucial considerations in mind. I’ve mentioned some important ones below:

Tip 1: Use a Relay at All Times

It’s not recommended to install a kill switch and leave it idle.

Many three-prong toggle switches lack the necessary amp capacity, leading to electrical issues that could cause the switch to melt or catch fire. Rather than taking chances, always use an automotive relay and an appropriately graded kill switch.

Tip 2: Install an Inline Fuse

Installing an inline fuse in your power cable is a crucial safety measure that keeps things safe in case of an electrical disaster.

Tip 3: Utilize an Appropriate Wire Gauge

Only use automotive wire that is sturdy enough to withstand the voltage. An electrical fire might arise from a thinner wire that cannot safely transmit voltage.

Tip 4: Keep your Fuel Pump Kill Switch Hidden

If you leave the kill switch in an easily accessible location, your installation will be useless.

Mount or hide the switch somewhere safe and accessible only to you.


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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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