LED Flasher (automotive or motorcycle)

I replaced the incandescent turn-signal bulbs in my Kawasaki Concours motorcycle with LEDs because 1) they brighter 2) they last longer and 3) they require less current than incandescent bulbs. Because they require less current, the standard flasher unit (the little box that makes your turn signals blink) senses the low current and thinks there is a bad bulb and it therefore won't function properly. So the standard flasher unit needs to be replaced with one that is compatible with LEDs. You can buy these, but where is the fun in that? I designed a simple LED-compatible flasher circuit and retrofit it into the original flasher case.

Step 1 Locate and remove the flasher unit

First locate and remove the flasher unit. This will be different for each vehicle. Consult your service manual for the location (or listen for the clicking noise when the flasher relay is operating).

Comments

[admin]

This is a great Instructable, but you need to add a main image of the final project to the intro step. Please do that and leave me a message when you have so that we can publish your work. Thanks!

[scd]

I've posted a picture of my Connie, which is where the new LED flasher is installed. It's working great :-) I've also updated a number of the steps with more detail.

[scd]

I searched for my instructable, but could not find it. Is it published now? Thanks, Scott

[lcupu]

nice

[kurshiukas]

What is the purpose of the power transistor? The original 555 sheet does not include it.

[Janno456]

If you think the on pointed out on my pic, then it's for toggling 12V on & off for you're turn signals. Simply it just acts as a switch thats been trigered by 555 timer output signal.

[kurshiukas]

Yes, this one. I just thought that turn switch itself provdes/cuts off current for the cirquit so if your turn switch is on off posittion you do not get 12V to the 1st point of jack and thus the pulsating output is not possible. if you switch it on 12V is provided so it should be possible to use the standart 555 cirquit, or am i missing something?

[Janno456]

It depends how is your vehicle turn signal circuit designed. Actually you don't need the transistor, in here it is only used to see if the 555 gives out desired signals. I had 2 wires connected to original relay so I measured which one of them gave out 12V. Finally I connected the 3 first 12V wires from schematic to the one that gave out 12V when ignition was on and the the transistor output wire I connected to the second original relay wire, which took the flashing signal out to my turn signal switch. Ground(-) wire I took directly from my bike battery. Result was exactly the same as with original relay. So when you turn on your ignition the LED D1 starts to blink with mentioned rate and switching your turn signal switch connects the transistor output with signal lights.

[kurshiukas]

Got it, Thanks!

[Janno456]

I made it, tried it and it worked well, except I couldn't get rid off one problem- when I turn on ignition and try my turn signal, it blinks very fast, but after some minutes has passed it works great as it should be. I tryed different capacitors and got some different results: for example using 2.2uF took longer to gain normal flashing rate than using 1uF. Didn't you had this problem, or can someone explayne me why this problem occurs?

[tyodz]

The instructable is great and would be useful. But it appears that the device will flash continuously even if the flasher switch is in the neutral position. Please correct me if my analysis was wrong. Thanks

[abadfart]

well the switch should kill power to the flasher all together

[tyodz]

Can you please provide a simplified diagram on how to use this flasher as a direct replacement for the standard flasher. Thanks very much.

[Splinter_Cas]

Great instructable... will be doing one of these myself.