DRL - Make this DRL (Day Time Running Light) Circuit for Your Car

Make this DRL (Day Time Running Light) Circuit for Your Car

The presented circuit of a DRL or a Day Time Running Light was requested by Mr.Senthil. Let's understand the complete design.

The Circuit Request

Hello Sir,

I'm an avid DIYer. Recently, i was looking to make a DRL(daytime running light) for my car using 1 watt smd LEDs.

But i couldn't find an appropriate circuit for my need. I want to drive Eight 1watt LEDs from my car battery.

I would very much appreciate if you could design a simple and rugged circuit to drive 8 x 1watt leds from a 12-14v input.

I'm also planning to add a heat-sink to dissipate any heat generated by the leds.
Thanks & Regards,

The Circuit Design

What's a DRL or Day Time Running Light Device:

A DRL is a safety car lighting device specifically assigned to moving vehicles for increasing the conspicuity of the vehicle during day time, especially when the daylight is accompanied with fog or during dull overcast days.It is normally fixed just beside the headlamps on either sides.

Normally a DRL system is in the form of constantly illuminated high intensity lamp. With the advent of modern High intensity LEDs, making a DRL lamp is matter of  less than  an hour.

As per the request the proposed day time running light or DRL circuit would be in the following form:

 DRL (Day Time Running Light) Circuit for Your Car


However in case you are interested to spice up the above idea a bit, and think that the system should do justice to the name that it has been specified, you would want to make it a literally "running" or chasing kinda thing!

Making a Chasing DRL Circuit

The DRL circuit discussed below shows how we can add a running effect to the above design and make it further interesting.

The circuit is actually a straightforward powerful LED light chaser circuit which is able to drive many 1 watt LeDs in a sequential manner.

The IC 4017 is a Johnsons Decade counter which generates a sequential switching at its 10 outputs in response to positive pulses fed at its pin#14. These pulses are referred to as clock signals.

As can be seen in the given circuit diagram, the IC 555 is configured in its basic astable multivibrator mode, and generates the required clocks for the IC 4017.

The clock pulses are taken from pin#3 of the IC555 and fed to pin#14 of IC4017.

In response to the above clocks, the output of the IC 4017 shifts a high logic sequence from pin#3 to pin#6. The moment it reaches pin#6, the sequence reverts to pin#3 and the cycle repeats.

Since only 8 LEDs are requested, pin#9 is connected to the reset pin of the IC so that the only 8 outputs become active with the required functions.

The speed at which this sequence may "run" or "chase" will depend on the setting of the 100k pot. Any value between 1 to 5 Hz may be set by suitably adjusting the pot.

The transistors respond to the sequencing high pulses at their bases and switch ON the connected 1 watt LEDs in the same pattern creating a powerful dazzling "running" LED light effect.

Since the illumination is very powerful, would become visible even during daytime and on foggy days and thus the circuit becomes very suitable as a DRL unit and may be used in cars as a Day Time Running Light device.

Running Chasing DRL (Day Time Running Light) Circuit for Your Car


Chasing Dark Spot LED DRL Circuit

For creating a "running dark spot effect" use PNP transistors in place of the NPN ones, connect the emitters to the positive, and connect the LEDs across the collectors and ground. Do not forget to reverse the LED polarity too.

62 thoughts on “Make this DRL (Day Time Running Light) Circuit for Your Car

  1. Have questions? Please feel free to post them through comments! Comments will be moderated and solved ASAP.
  2. I am looking for a circuit to dim some LED Day Time Running lights, whilst the indicator is flashing. ie Full brighness when indicator is OFF(not flashing) and 50% brightness but on constant while indicator is flashing. like with Audis.


    No Indicator(not flashing) = LED DRL on full brightness
    Indicator flashing = DRL LED on 50% brightness. DRL LED's must not flash.
    If headlight is on DRL LED on 50% brightness. DRL LED's must not flash.

    DRL = Day Time Running Lights.

    Can you assist?

    • you can do it in this way:

      Use a relay with a 470uF/25V cap connected parallel to its coil.

      Connect resistors at it N/O and N/C.

      Make the free ends of the resistors common and connect with the respective DRL positive string.

      Connect the pole of the relay with supply(+).

      Connect the coil terminal which has (+) of the 470u with two 1N4007 diodes cathodes (cathodes made common).

      Connect the free diode anodes, one with the flasher output (+) and the other with the headlight (+).

      connect the other coil/cap end and the DRL negative to ground.

      Select the resistors such that, position N/C produces 100% glow while N/O produces 50% of that.

    • Hi Rob, surely I can do it.

      Would you mind sending a brief write-up explaining the above functions elaborately as per your understanding. The longer the better;)

      It would help me to add a content with the schematic.

    • Hi Swags,
      I'll try and explain in more detail. I want a module which will connect to a set of aftermarket DRLs that will allow them to turn on when the cars ignition is on (ideally via direct battery connection with a voltage sensor to turn them on but if not via ignition live feed). The module needs to connect to the headlight so that when it is turned on the DRLs dim to 50%. The module also needs to dim the DRLs when the indicator is activated on that particular side of the car (right DRL dims when right indicator is turned on etc.). This aspect isn't necessary when the headlights are on as the DRLs are already dim. When the indicators turn off I would like the DRL to fade back to full brightness say over a period of 2 seconds or similar.
      It is basically just like the new Audi DRLs which are built into their headlights.

      I hope this is enough information for you to produce a schematic but if not I can try and give you some more information. Also, using your relay method would be best!



  3. Hi Swagtam Sir
    Im a hobbyist. Looking for a driver circuit for 8 x 0.5W SMD LED for DRL.
    Can you please suggest me which value of resistor I use?

    Thanks in advance
    Waiting for ur reply sir.
    Ajay Sehgal

  4. Dear sir I have accurate current controlled circuit which is used in audi,BMW, benz for long life of LED's. I used this circuit since 2 years as a my bike headlights and DRL in my car. Same lighting since 2 years. I copy it from audi drl. It's work 3 led s in series and can run any of need. Just need some resistors, transistor, mosfet with heat sink

  5. Thank you for the diagram, sir. Could you please go a step further for me?

    I would like to install a DRL that also turns on my taillights and that automatically turn off both when the headlights or high beams are turned on. Would you be able to describe to to make such a setup?

    • You will have to do the following steps:

      Take a 12V relay, connect its coil one end to negative supply.
      Connect its other terminal to the headlamp switch positive output, so that now whenever head light is switched ON, the relay also activates closing its N/O contacts.

      Now just simply you have wire the above relays N/C contact and pole, with the DRL and the tail lamp such that the DRL and the taillight lamps get their ground or negative suppies via the N/C contacts.

      It means only as long as the above relay is in a non-activated mode, the DRL and the taillight would get access to the negative supply for switching ON, the moment the relay is activated the DRL and the taillights would be cut off from the negative ;line and will no longer be able to illuminate.

  6. Hi Swagatam.

    I would like to build circuit with HID 2x35W and DRL led 2×8 (each 1W). HID running at dark and LED diodes at day, could be ambient light sensitive.

    The lights will work just with key in ignition (keysense +6V).


  7. Hi sir,
    I would like to build a brake lamp project using 1 watt high power leds, consisting of 12-15 leds.
    the leds would light on dim praking lights and would light full on brake pedal press. kindly provide me a circuit..
    kind regards,

  8. HI I have a similar design as the first schematic but only 6 LEDs per site (Left/Richt). However my leds are 1 Watt high power LED (3,4-3,6 Vf and 300-350mA If). I would like to use the 10,8 – 13,8V battery from my car and use these as my DRL.

    What kind of schematic would I need to create?

    Thanks for your help.

    • you can make two strings of 3 LEDs each…with a 8 ohm 1 watt resistor with each string…then you can put these two strings in parallel on each channel

      make sure the LEDs are mounted on heatsinks

  9. Thanks. I did my maths too. Came to same conclusion.

    One additional note: what do I need to do if the signal that I have is a PWM signal instead of 12v on/off. Can I use this with the same schematic? I can add another wire from the battery 12v but would like to use this drl signal which will originate from the board control module.

    Thanks again.

    • If the PWM current is adequately rated then it may be directly fed to the DRL lamps via the switch, if the PWM input is weak, then you might need a transistor driver in the middle.

      you can do it using a TIP127 transistor…connect its collector to the DRL, emitter to the 12V positive through the DRL switch….and the base can be connected with the PWM input via a 10k resistor.

  10. Dear Sir,what if I would drive 100 Incandescent lights to make a running light?
    Will the Chip 4017,have another version that has Many Outputs up to 100…
    Or I will just have to reconfigure the pins to make it perform up 100?
    Should I just use a relay to power the incandescent from the mains?

    Thank You Very Much Sir!

    • Dear Rajkumar,
      assuming the input to be 14V and the number of LED = 4, the value of the resistor will be
      14 – (3.3 x 4) / 0.15 = 5.33 ohms
      wattage = 0.8 x 0.15 = 0.12….so a 1/4 watt will do.

  11. Hello Sir! Thanks for all your contribution to the common knowledge of mankind! You provided great ideas/examples! I came to your site in search for a voltage-stabilized circuit so that the LEDs are neither overdriven nor underutilized, when operated from the cars 12-14V. Do you have something in your mind/archive? 🙂 Thanks a lot!

  12. Hi,
    Interested in putting DRLs in a classic car, 63 Buick Riviera and want to stay with original lighting. Wish to install LED bright globes (single contact) as DRL where current park light is fitted. It has another park light in the turn signal section above so no issue.

    However I also wish to dim/turn off one side when cornering to make that lamp easier to see.

    I am not an electronics whizz but can solder wires and put together components to make a simple circuit. And just need a simple shopping list as well.

    Can you assist here?
    kind regards

    • hi, connect the 5 LEDs in parallel with each LED having a series 2 ohm 1 watt resistor…connect the ends of this parallel connection with the battery through the DRL switch.

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