Swapping the stock indicators for slim LED ones is one of the most popular changes riders make. It tidies up the look of the bike, LEDs are brighter and react faster than bulbs, and they last much longer.
There's one catch nearly everyone runs into, though. You fit the new indicators, switch them on, and they flash at double speed. Here's why that happens, how to fix it, and what to check before you fit them.
Why LED indicators flash fast (hyper flash)
Older bikes use a flasher relay that's designed around the power draw of filament bulbs. It also has a simple safety feature: if a bulb blows, the current drops, and the relay flashes faster to warn you.
LED indicators use a tiny fraction of the power of a normal bulb. To the relay, that looks exactly like a blown bulb, so it starts flashing fast. This is called hyper flash. The indicators themselves are fine. The relay just doesn't recognise them.
Some bikes also show a warning light on the dash, or the indicators don't flash at all and just stay on.
Fix 1: an LED flasher relay
The neatest fix on most older bikes is to swap the original flasher relay for an LED-compatible one. These relays flash at a normal rate no matter how much power the indicators draw, so they work with LEDs, bulbs or a mix of both.
The relay is usually a small box under the seat or behind a side panel, plugged into the wiring loom. Check the number of pins on your original relay, as two- and three-pin versions are common, and match it. In many cases it's a straight plug-in swap.
Fix 2: load resistors
If you can't find a suitable relay, or your bike controls the indicators through an electronic module, load resistors are the other option. A resistor is wired in alongside each LED indicator and adds back the load the relay expects to see.
They work, but there are a couple of things to know:
- You need one resistor per indicator, wired in parallel
- Resistors get hot, because they turn the extra power into heat. Mount them on a metal surface away from plastic, wiring and anything that could melt.
- They cancel out one of the benefits of LEDs, which is lower power use
Newer bikes
Many newer bikes don't use a traditional flasher relay. Instead, the indicators are controlled by an electronic module. On these bikes, a relay swap may not be possible, and you might need load resistors, an adapter made for that model, or a change in the bike's settings. If you're not sure how your bike's indicators work, a motorcycle dealer or technician can tell you quickly.
Wiring them up
Most aftermarket indicators come with two wires, one positive and one negative. Unlike bulbs, LEDs only work one way round, so if an indicator doesn't light, try swapping the wires.
A few tips for a tidy, reliable job:
- Use proper crimp connectors or solder and heat-shrink, not twisted wires and tape
- Route the cables away from hot exhausts and sharp edges
- Leave enough slack around the steering head for full lock in both directions
- Check everything works before you refit the seat and panels
Some indicators include a running light, which needs a third wire. Check the product details to see how it's wired.
Building a custom bike or a switch panel from scratch? Our universal turn signal rocker switch is rated at 20A on 12V and suits motorcycles, ATVs and other vehicles.
Staying legal
Indicators on a road bike must meet UK lighting rules. Rules cover things like the colour (amber), how bright they are, how far apart they're mounted, and the flash rate. Check the product details for E-marking, and check the current rules before you fit them, especially if you're mounting them closer together than the originals.
Many compact indicators are designed to sit close to the bodywork or mount on the number plate hanger. If you're fitting a tail tidy at the same time, make sure the rear indicators still meet the spacing requirements.
Sequential and integrated indicators
Sequential indicators light up in a sweeping pattern rather than flashing on and off all at once. Others combine the indicator with a brake light or running light in one unit. These usually have their own wiring requirements, so read the fitting instructions carefully before you start.
Shop motorcycle indicators
Many indicators are made for particular bikes, so they mount on the original points and are easier to wire in. A few examples from our range:
- LED turn signal light for the Yamaha R3, R125, MT-03 and MT-125, for front or rear
- LED turn signal mirror block-off pair for the BMW S 1000 RR from 2019
- Rear view mirrors with built-in LED turn signals for the Yamaha YZF-R7 and YZF-R9
You'll find more in our motorcycle lighting and indicators range. Always check the bikes listed on the product page before ordering, and if you're not sure, get in touch with your make, model and year. If you're planning to add more lights while you're at it, our guide to motorcycle spotlights and driving lights covers mounting and wiring.
This article is a general guide only. If you're not comfortable working on your bike's electrics, ask a qualified motorcycle technician.