So I have this modification to my electrical system on a motorcycle. The voltage on my motorcycle is 12V and I switched from classic lights to led light (both front and rear). My problem (which I expected) is the now the light are not flashing, they are just ON. I bought some load resistors designed for this. I have 2 pairs (10w 10Ω). I don't know where to connect them. I have below the electrical diagram and marked with red where are those lights, switch and relay. I suppose that I should put them between the switch and the lights (on those two wires near CH and DG)

enter image description here

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    \$\begingroup\$ You could try and find an electronic flasher unit instead of the classic bi-metallic unit. \$\endgroup\$
    – Trevor_G
    Mar 20, 2017 at 21:12
  • \$\begingroup\$ I kinda want to go with the resistors, I don't have experience with this and I don't want to complicate things. \$\endgroup\$ Mar 20, 2017 at 21:14
  • \$\begingroup\$ Then they should go in parallel with the lights. The "flasher" works when the current through the lamps heat the metal strip in the flasher and it bends and breaks the circuit. BY changing to LEDs you no longer have enough current, so you need to use the R to simulate the lamp load. \$\endgroup\$
    – Trevor_G
    Mar 20, 2017 at 21:17
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    \$\begingroup\$ Think of it this way.. If you just took out the bulbs entirely, where would you put the resistor to trick the thing into thinking the bulb was still there. \$\endgroup\$
    – Trevor_G
    Mar 20, 2017 at 21:36
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    \$\begingroup\$ In parallel. Yeah, I understand now. Thanks. I will split the wire which conducts current to lights (before they split to rear and front) and add the red wire (from resistor) and the black wire from resistor somewhere to chassis ground. I hope that will work. \$\endgroup\$ Mar 20, 2017 at 21:39

2 Answers 2


As noted in the comments, Flasher Load Resistors are wired in parallel to the led replacement lights, when using the original Flasher relay module. The flasher is probably a thermal one, and won't break because your led lights don't draw the current needed to heat it up to make it flash.

enter image description here

You should connect the load resistors between 31 the turn signal switch and Ground, one per turn line (Ch = Chocolate and Dg = Dark Green wires).

Hey, I just installed one resistor (after the relay) and the indicator light (from the tank), number 20 on the above electrical sketch it is turning on and off all the time, even if I cancel the left or right signal. I don't understand why. Everything works find beside that. Can't figure it out why is this happening. – user3672802 Apr 3 '17 at 12:48

This happens because 20, the turn signal indicator, is wired in parallel with the flasher relay. By connecting the load resistor between 32 and 31, to ground, you provide a path to ground for both 32 and 20. This path to ground is normally through the turn signal lamps. With the path to ground, you get this behavior because the relay turns on, starts conducting, gets hot, turns off, so the turn signal indicator 20 turns on. As the relay cools down, it closes again, shorting out the turn indicator, turning it back off.

So again, put the load resistor after 31.

Or as the other answer says, buy a new, electronic flasher relay that's designed to work with leds or incandescent lights, without the need to use load resistors. Using load resistors defeats half the benefit of led lights, which is using less power.


There is existing product in the market to solve this issue https://www.ebay.com.au/itm/2-Pin-Speed-Adjustable-LED-Flasher-Relay-Motorcycle-Turn-Signal-Indicator-6/292032447949

Works for most motorcycle/bike to fix the LED bulbs related turn signal light hyper flashing, not function properly issues.
Completely waterproof design.
Directly replace the OEM two-pin flasher.
Eliminate the need for tapping wires to install the load resistors.
Allow LED bulbs to blink at the normal rate.

Work for most Motorcycles such as:
for Honda, for Kawasaki, for KTM, for Suzuki, for Yamaha and many other brands as well

Operating Voltage: 12V.
Max Power: 42W.
Flashing Frequency: 50 times/min to 200 times/min.
Switch Power: 0.02A to 12A

You might have to check if this one is compatible with your bike or some variation (eg 3 pin ).

I have personally used this on a Honda, it worked fine.

  • \$\begingroup\$ We shy away from Ebay, and you MUST declare the link to any quoted material. If it is your summary do not put it in quotes. \$\endgroup\$
    – user105652
    Mar 23, 2018 at 3:39

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