Symptoms
- One or more turn signals don't light up at all
- Signals blink much faster than normal
- Signals work on one side but not the other
Likely causes
- CommonBurned-out turn signal bulbA dead bulb changes the circuit's resistance, which often causes the remaining signal to blink rapidly.
- CommonBlown turn signal fuseIf all signals are out at once, a shared fuse is a likely and easy first check.
- PossibleCorroded bulb socket or connectorMoisture intrusion at the bulb socket can prevent good contact even with a working bulb.
- PossibleFailing flasher relayAn aging relay can cause erratic or non-functioning signals even with good bulbs and fuses.
What to do
- Check which signals are affected: if only one side blinks fast or is out, suspect that specific bulb first.
- Inspect the affected bulb for a broken filament or blackened glass, and replace it with the correct type.
- If all signals are out, check the dedicated turn signal fuse in the fuse box.
- Check the bulb socket for corrosion, especially on bikes exposed to rain or road spray regularly.
- If bulbs and fuses are fine but signals are still erratic, the flasher relay itself may need replacement, which is usually an inexpensive plug-in part.
- Confirm proper operation on both sides after any repair before riding, since signals are important for safety and legal riding.
Tools and parts
- Screwdriver
Turn signal bulb, correct typeSearch: “turn signal bulb for [your bike year make model]”
When to call a pro
If bulbs, fuses, and sockets all check out but signals remain erratic, have a mechanic check or replace the flasher relay and wiring.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.