How to Wire a Relay for Motorbike Spot Lights

We're frequently asked, “should I install a relay with the lights?”  The answer is YES! We did extensive research, consulting motorbike experts to be able to design this custom Relay Wiring Harness for motorbike spot lights. 

Here is a diagram showing you how to connect them using a relay.

WHAT IS A RELAY?

A relay is an electrical switch.  It allows a low current “switch” circuit to control the electricity flow of a high-current circuit.

DO I NEED A RELAY?

When you are not using a relay, the control switch needs to be able to handle the full current of the installed lights.  For lower powered lights it is possible to do so, but it is generally good practice to install a switch with an in-line fuse.  When the current increases, this switch needs to be big.  If you do not install a relay and use a switch, you could end up overheating the switch, melting the wires, and reducing the current that is getting to your lights, making them less bright.

HOW TO WIRE YOUR LIGHT USING A RELAY

The relay will have 4 points on it, marked 30, 87, 85 and 86.  That is kind of cryptic, isn’t it?

The left side is the pin out of the point is sticking out from at the bottom and then the right side is showing a schematic representation of the relay circuitry.

30 and 87 create the switch to your lights.  By default this switch is open, so the current cannot get from the battery to your lights.

30 – is your power source for your light.  It connects to the positive (+) side of your battery or to a switched power source that only gets power when your ignition is on.
87 – goes to the positive side of your LED lights.

85 and 86 use electrical current to create a magnetic force, which then closes the 30 to 87 switch and allows the electricity to flow to your lights.  Without this current, no magnetic force is created, so the 30 to 87 switch stays open, and your lights stay off.

85 – connects to the power source that you want controlling the switch.  For example, you could splice a wire off your high beam wire or off your backup light wire
86 – connect to a ground.

(Note: 85 and 86 can be reversed).

UNCERTAIN HOW TO DO THIS YOURSELF?  HAVE A LOOK AT OUR PREWIRED RELAY WIRING HARNESS FOR TWO MOTORBIKE SPOT LIGHTS WITH A 10W RATING.