How to wire a 5 pin relay
Contents
What Is a Relay?
A relay is an electromagnet switch, which uses a very small amount of electricity to control a much larger amount of electricity. It's kind of like a child with a well-trained pet Tyrannosaurus Rex. The child (small electricity) can tell the T-Rex (big electricity) what to do because they are best friends. If the child wants the T-Rex to flip over a minivan, he just tells his T-Rex, and the minivan is flipped. The child stays safely away from all the dangerous work, and the T-Rex doesn't even break a sweat, because they are both sized appropriately for the task they are doing. The large switch (T-Rex) inside a 4 or 5-pin relay is told what to do by a small switch (child) inside the relay.
Relays are also often used to control the flow of electricity in a completely different location from the controller. For example: The child from Massachusetts goes to visit Grandma in Florida and leaves his beloved T-Rex best friend at home because he doesn't fit inside the plane. The child then calls his T-Rex on the phone and asks the T-Rex to flip another minivan. The T-Rex happily does this for the child. Again, no effort for the child, just a T-Rex controlled from a long distance. A relay works the same way. A high amperage circuit (T-Rex) for an electric fuel pump can be turned on under the car while being controlled by a teeny-tiny low amperage switch (child) mounted in the car's dashboard. The dashboard switch never has to see the high amperage that the fuel pump is drawing, it is just telling the big fuel pump relay to turn on or off.
Why Do You Need a Relay?
In the automotive world, relays allow you to use a small switch inside the car, to remotely control the flow of electricity through a larger amperage circuit located any distance away from the switch. Most switches used in the automotive world are only rated to handle a small amount of amperage. Many circuits in a car are rated at amperages larger than the switches are rated for, which means if the circuit were to be wired through a switch directly, the switch would melt, break, and possibly burn. However, if a relay is used, the circuit becomes much safer and more reliable. Most relays are rated much higher than switches. So you could use a 5 amp switch to remotely control the 30 amp relay. The 5 amp switch tells the relay to turn on and off. The 30 amp relay controls the high amperage circuit.
How to Wire a 5 Pin Relay with a Positive trigger?
Pin 30 - Power goes from the battery and into this pin, through a fuse.
Pin 87 - Power comes out of this and goes to any accessory when your switch is turned ON.
Pin 86 - Power goes into this from the switch.
Pin 85 - This goes directly to ground.
Pin 87A - Power comes out of this when the switch is OFF. It do not need to be used, and can be ignored entirely if it is not needed.
How to Wire a 5 Pin Relay with a Negative trigger?
Pin 30 - Power goes from the battery and into this pin, through a fuse.
Pin 87 - Power comes out of this and goes to any accessory when your switch is turned ON.
Pin 86 - Power goes into this, jumped over with a wire from pin 30.
Pin 85 - This goes to one side of your switch.
Pin 87A - Power comes out of this when the switch is OFF. It do not need to be used, and can be ignored entirely if it is not needed.
Switch - One side of the switch gets the ground wire from pin 85, the other side of the switch goes to ground. Unfortunately, with this design, you cannot easily have a light-up switch.
