Just curious, because someone told me I needed a fuel pump relay to ensure my fuel pump is getting a steady level of voltage. I bought an aftermarket fuel pump relay kit, and instead of wiring it to the ignition, I planned to wire it to a toggle switch, which I figured would double as a cheap vehicle "anti-theft" system. After talking with a friend about this, he said if I was going to run it to a toggle switch, that a relay isn't necessary. He said it's only necessary if running it through the ignition. Is this true? I thought the relay did more than that...can anyone help???

 

It's far better to use the relay. You get potentially better power transfer to the pump and you don't have a need for high current running through a switch (much safer).

 

So you'd agree that even if I run a switch, I need a relay, right? (this was my original plan, and someone tried telling me otherwise)

 

Yeah, to operate the relay, you are going to need a switch (if you want manual control).

 

And you can run the relay with a much "lighter" (smaller amp rating) switch. The relay is typically rated at 35 amps. A 35 amp switch would be bulky. With a relay, the switch only needs to handle the tiny amperage required to activate the coil in the relay.