In this post, we are going to go over some of the more common problems you may come across after installing aftermarket LED indicator lights on your motorcycle or car. With some cheap LED bulbs you may find that your LED indicator lights either stop working, flash too fast, blink at the same time, or are not bright enough.
Table of Contents
Motorcycle indicators not flashing
This is a very common problem that can work with either incandescent bulbs or newer LED lights. Often it is just a case of your flasher relay going bad. These can either be electronic solid-state relays or mechanical 12v relays.
If your motorcycle indicators are not working try changing out the flasher relay. If you have just replaced the flashing relay and your indicators are not blinking you may have wired it up backwards. There are positive and negative terminals on the flasher relay that need to be wired up correctly.
It is not only affecting turn signals but aftermarket led tail lights often have this problem as well.
Blown fuse
Check that the fuse is ok for the indicators or tail light. Moisture could have worked into the indicators and shorted out the bulb. This will cause the fuse to blow. Replace the fuse and dry out the moisture in each indicator LED light.
I would also check that the key on/off switch is fully activated and turned on. I have come across a situation where my key was between aux and on. My indicators were not working at all. Once I turned my motorcycle key fully on then the indicators started flashing again.
Blown Bulb
One of the light bulbs has burnt out. This is the main reason people are going to LED lights on their motorcycles or car. Bulbs are easy to replace if you stick with incandescent bulbs. Changing over to LED tail and turn signal lights can cause other issues.
Try not to touch the glass bulbs with your fingers as it will leave an oily fingerprint that will stain the glass bulb when it heats up. Always use a clean cloth or gloves to remove and replace the 12v automotive light globe.
Ground Wire Faulty
One of your turn signal wires could be reversed or grounded improperly. This will cause a hot joint and LED turn signal to not flash. Make sure all wires are tight and there is no corrosion on the terminals. A bad ground can cause a high resistance joint that can cause all sorts of strange electrical issues such as s LED turn signal not flashing.
If you suspect a faulty ground you will have to trace the wire back and check each connection. Be sure to also check the terminals on the battery these often corrode due to the gassing of the battery acid.
Flat Battery
A faulty flat battery can cause insufficient power to be delivered to the turn signals. LED indicators are very susceptible to low voltages and will often fail to power up.
A short in a battery can cause a huge power drain so be sure to check the voltage of the motorcycle or car battery. At rest, a fully charged battery should be over 12.6 volts but on the charge, it should be around 13.8 to 14.3 volts DC.
Bad Flasher Relay
Flasher relays are often reliable but they can go bad from time to time. They are usually 2 or 3 wire flasher relays and are plug-and-play. They should flash between 80-100 cycles per minute. I will cover more about the LED turn signal not flashing problem and how I fixed the hyper blinking further down in the article.
Fault Codes
Check your dash if you have any fault codes logged. I use a Bluetooth OBD2 scanner and a Yamaha 4-pin cable to check what fault codes are logged in the ECU.
From here you will get a clue on what to look for within your motorcycle wiring. You may even be able to reset these codes if the fault has cleared. Here is the current full Yamaha fault code list available from 2014-2021.
Other Motorcycle LED indicators problems
Shorting out the wires will cause a blown fuse and other problems with your motorcycle. Be sure when you are wiring up your new LED lights to insulate them well. The above picture is my process of installing a new Yamaha MT07 fender eliminator.
Sometimes your LED indicators will flash too fast. This rapid flashing is not normal and could cause unwanted attention or even a defect for your motorcycle.
This Hyper flashing event is when the turn signals blink faster than your old stock incandescent bulbs. It is a common problem with cheaper aftermarket LED vehicle lights. The reason for this is that the flasher relay is not detecting much current flow from the LED lights so it powers down. It then receives a signal to start flashing again but there is not much current flow again so it shuts down. Don’t worry there is an easy fix.
How many load resistors do I need for LED turn signals?
You will need one 50 watt load resistor per LED turn signal or tail light, for correct operation and elimination of hyper flash. So for each vehicle, you will need four 50w load resistors wired in parallel with each indicator.
Sometimes depending on the flasher relay, you can get away with only using one 50-watt resistor on each side of the car or motorcycle. This tricks the flasher relay into seeing a smaller power draw.
Load resistor parallel or series?
You will need to wire the load resistor in parallel with the LED turn signal. This will increase the power flow from the active wire to the negative ground circuit.
Many people make the mistake of wiring the load resistor in series with the LED. This will decrease the current flow and will increase hyper flashing. It is one of the reasons LED turn signals are not flashing properly.
How to fix hyper flash without a resistor
The low power draw from LED lights is a blessing and a curse. There are two ways to fix this problem either install a LED-approved 2-wire flasher relay, (the easy way) or install a 50w 6-Ohm load resistor in the circuit of each bulb.
Each solution will fix the problem but I went with just replacing the flasher relay. This relay is just a two-wire plug that was easy to get to and replace. Newer motorcycles are now coming with LED-compatible flasher relays.
Benefits of a LED flasher relay
- The completely waterproof design directly replaces the OEM two-wire flasher relay.
- Eliminates the need for tapping and soldering wires to install the 50-watt load resistors on each light.
- LED bulbs will now blink at the normal rate using a LED flasher relay. No more hyper flashing.
- Compatible with most Japanese motorcycles such as Honda, Kawasaki, Suzuki, Yamaha, and many other brands as well.
- Operating Voltage: 12V (11V-15V)
- Max Power: 150W
- Flashing Frequency: 90 Times/Min
- Switch Power: 0.02A to 12A
- Operating Temperature: -40°C to +80°C
- LED turn signal not flashing fix
Yamaha MT07 Motorcycle LED light wiring diagram
I have included the Yamaha MT07 motorcycle LED light wiring diagram which I used to fault find a lighting problem. Most motorcycle wiring diagrams will be specific to that brand and model. The color codes help to trace the wires through.
As you can see the flasher relay is number 65 and it receives power through fuse numbers 4 and 8. This is dependant on the position of the key switch. This is why sometimes you may have power in one key position and not the other. On a side note, the flasher relay is only two-wire so this new LED flash relay will work. It is plug-and-play.
On my motorcycle, the LED turn signal not flashing problem was caused by a blown fuse due to a damaged cable that had worn through the insulation.
Using LED Turn Signals on a vintage motorcycle.
Vintage motorcycles don’t have a lot of diodes installed that new motorcycles have in the wiring harness. So if you want to install LED lights on a vintage motorcycle you may need to use a diode and a load resistor on each circuit.
The video below explains it well with some examples and problems you may run into.
Conclusion
Faut finding an electrical problem on a motorcycle can be a frustrating process. There is not a lot of room to work with so it will be handy to have a wiring diagram.
If you have installed a new set of motorcycle led indicators and they are not flashing then hopefully a load resistor or a new LED relay will fix the problem.
The load resistor needs to be wired in parallel with the active terminal and the ground wire going to each LED light. So use a multimeter to find where the 12v is going to each bulb. Take your time and remember to insulate each wire well as motorcycles vibrate a lot and can quickly short out aftermarket led indicator lights.
I am a qualified Industrial Electrician for the past 20 years and I love to share my knowledge on home repair and maintenance jobs.
I love fast toys like Motorcycles, Cars, Jetskis, Boats, and Computers so writing about them is easy. Working on them is fun.
To keeps costs down I do all my own mods, repairs, and servicing. These skills I want to share with everyone. DIY is a skill everyone can learn.
