Relays
About Relays
A relay is an electrically operated switch. A small current from a switch or control circuit closes it and lets a much larger current flow to the part being run, such as a horn, light or starter. Riders shop here to replace a relay that clicks but does nothing, to add one when installing lights or a horn, or to fix a turn signal that stopped blinking or blinks too fast.
Start by working out which kind you need. Flasher relays control how the turn signals blink and are listed by type and by the number of pins, so match the plug and the voltage. A starter relay, which handles the heavy starter current, and general-purpose micro relays are used for accessories. Many micro relays come with a socket or a socket kit with wires and terminals, so that you can wire them in without cutting into the main harness. Some include a diode. Check the amp rating against the load, and if you change to LED turn signals, use a flasher made for the lower load.
Brands here include Drag Specialties, Standard Motor Products, Grote, Rigid Industries and Koso North America. Related parts are Fuses & Fuse Boxes, Horns & Horn Covers and Batteries. For a relay made for your machine, pick it in the Ride Finder at the top of the page.
FAQs on motorcycle relays
How do I test a suspect motorcycle relay?
A failed relay can click without powering the part, fail to click at all, or work only sometimes. Swapping in a known-good relay of the same type is a simple test. If the symptoms follow the relay, replace it. Also check the fuse and connections.
Why do my turn signals blink fast after installing LEDs?
LED signals draw much less current than the original bulbs, and many flasher relays read that as a burned-out bulb and blink fast. An LED-compatible flasher, or load resistors made for the purpose, restores a normal blink rate. Check the instructions for your signals.
Do I need a relay for aftermarket lights or a horn?
Often, yes. High-draw accessories can overload the original switch and wiring, and a relay lets the battery feed the accessory directly while the switch only triggers the relay. Follow the accessory's instructions and use a fuse rated for the circuit.
What does a diode in a relay do?
A diode across the relay's coil absorbs the voltage spike that appears when the coil switches off, which protects nearby electronics. Diode relays can be polarity-sensitive, so wire them as the instructions show.
Can I use a car relay on a motorcycle or ATV?
Sometimes. A relay works in any 12-volt system if its voltage, amp rating and terminal layout match the job. Vibration and moisture are harder on a motorcycle or ATV, so a relay and socket sold for powersports use is the safer choice.
