Honda Crv Led Turn Signal Pwm conversion


i have changed all bulbs with leds in the car. Now i am trying to convert led flasher signal to 200 hz.

My plan is to remove fuse and add a mosfet that will generate frequency using arduino
like this;

(positive fuse pin 1) ==>>> (fuse)==>>> (mosfet=200hz)==>>> (negative fuse pin 2)

My questions are;

  • Will 200hz damage flasher relay?
  • Wich mosfet do you reccomend? (npn or pnp)
  • Which type of signal do you reccomend? ( saw tooth, square etc) (if you could share a arduino code it would be very much apreciated)

thank you

I am not sure what you mean about using a mosfet to generate a frequency. An Arduino can generate a frequency that can be amplified by the mosfet to 12v. It would be easier to use a 555ic to generate the frequency and not bother with an Arduino at all.

Connecting your circuit at the fuse location will not work. The frequency will not pass through the flasher it will just slow the flash rate or stop it altogether. You will need to either replace the flasher with your circuit or place it after the flasher.

Check your local laws it is very likely you could generate unwanted attention from the cops.

EDIT: Doh! At 200hz the will only dim the led's you cannot see the flashing at that rate

Why do you try to convert it to 200Hz? They just work don't they?

Also, the fuse box is a place for fuses, not for electronics. So leave the fuse as it is and insert circuitry somewhere else.

And 200Hz is wayy to fast for a relay, yes.

What do you really want to do? None of what you have said so far makes sense to me.

Thank you Hutkiks, Septillion and paulcet for your replies.

I am sorry for not being clear about the aim of project;

when you look at modern cars, they use leds and they drive them with some frequency for power efficiency and better visibility.

please check pictures attached for example.

I will do as Hutkikz recommend andplace generator after flasher relay. however it is hard to adjust frequency with 555. Arduino is easier to trim the frequency.


It has nothing to do with visibility. It's just dimming them... And if you don't need to dim them, then don't.

And when you dim you don't want to change the frequency but the duty cycle. You want the frequncy as high as you can to avoid the effects of the pictures (hate those cars). Probably the default +-400Hz of the Arduino is a bit to slow. The +-900Hz of pin 5 and 6 is already better. But it's not to hard to change pin 9/10/11/3 to 4kHz but you have to alter the timer settings.

And changing duty cycle and frequency with a 555 isn't that hard... No programming but not hard. And it's indeed by far the simplest method of dimming the LEDs

And indeed, replacing the blink relay is the easiest place to do it. But then you also have to do the blink and interface the switches. But as long as you don't want to dim them why do it? Dimming them only makes them less bright aka less visible. Yes, the power consumption is also less but who cares after replacing a bulb with LEDs?

The factories use many more led's than are used in those bulb replacement types and that is the reason for a certain amount of dimming. And as Septillion stated you have already increased effiency compared to what was there.

I work in a automotive restoration shop and have put these in several cars and no one has ever thought they were to bright. The only way to increase visibility would be to add more led's and that would require a whole different approach.

Dear Septillion and Hutkikz;

Leds that are installed in the car are already 9-12 Volts led chips. So 15 volts default alternator voltage need to be dimmed. (at the moment leds are driven by resistors)

Right now turn signals are not very visible. So if there would be some fast flickering in the lights, they would be more efficient and people can understand the car is tending to turn. What do you think?

Full power will always be brightest "flickering" will always dim them and make them less visible even if you were to slow the rate down to where you would actually see the flicker(like 20hz).

If you are using the style that fits in a regular bulb socket they will already be set up to work at the cars voltage. I have found the cheap ones are junk and will not be bright enough. no matter what you do.
Here are what I use: expensive but they work well

I agree with Hutkikz. If they are not visible enough now then they are simply not bright enough. making them flicker doesn't make them more visible. It dims them and makes them annoying.

Indeed the key question is, what did you use to replace them with? If you just bought led bulb replacements you're fine. No need to change the voltage with a resistor of annoy people with it flicker them. Even cheap one are usually bright enough but if they will last long enough...