Christian picked up a Painless Performance electric fan relay kit with a thermostatic ... find the fan manufacturer's supplied wiring diagram. If you're still not sure, once you've completed ...

This is depicted in the professionally-rendered diagram below. From here you can see that, to use a relay to turn on the electric motor labeled “M,” you ground the negative wire of the motor ...

There’s a few open source options out there for creating electrical schematics ... there’s been limited options for creating wiring diagrams. Often these are created in Microsoft’s Visio ...

so you can use a low-amp switch and small-gauge wire (even on long runs) to hook it up to the relay. For the electric fuel pump application, the relay-actuating switch will be a common three-prong ...