Help out an electrical idiot. What are the relays for?


Go Dawgs
Jun 19, 2001
In all the DIY water injection scematics, they show two relays that should be installed. What do the relays do? Sorry to be so ignorant.

I relay is an electro-magnetic switch.

Basically you have 4 wires.
1 from you 12V supply to the relay
1 from the relay to your fan/fuel pump/water pump
1 low voltage wire from a toggle switch
1 ground

Example: A electric fan

you have to get 12V to your fan to turn it on and off, but you would need a huge switch to handle the current draw. A relay allows you to use a small switch for low current/voltages.

Basically when you flip your switch the relay closes and connects the circuit from the 12V supply to the you won't need the huge high amp switch.

They come in pretty handy. They are about 1" cube.