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 minivan is flipped. The child does not have to do any dangerous work, and neither does the T-Rex, because they are both sized appropriately the task they are doing.
Relays are also often used to control the flow of electricity in a different location from the controller. For example: The child from Massachusetts goes to visit Grandma in Florida without his T-Rex best friend. He calls his T-Rex on the phone and asks the T-Rex to flip another minivan. The T-Rex happily does this for him. Again, no effort for the child, just a T-Rex controlled from a long distance. A relay works the same way. A high amperage electric fuel pump (T-Rex) can be turned on under the car while being controlled by a teeny-tiny low amperage switch (child) mounted in a car's dashboard.
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. 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.
