How to turn BRZ Headlight LED into DRL
 

Hey guys, first off I wanted to say thanks to everyone who makes this forum possible. This community is by far the best I've ever belonged to. That being said I felt I should contribute. I have extensive electrical knowledge so what better thing to modify than our headlights. I personally feel Subaru fell short in this department, the LED horse shoe is already there so why not take advantage of it! First things first this mod isn't hard but should only be done if you're confident. Secondly, I will not take responsibility if you burn down your car, house, or neighborhood (very unlikely). Third, I'm more than willing to help out with any questions so feel free to send me a PM.

Parts/tool list
solder and iron
socket wrench and 10mm socket
screw drivers
multimeter
wire strippers
electrical tape/heat shrink
18-12 gauge wire
diodes which I picked up at my local radio shack. http://www.radioshack.com/product/in...ductId=2062591
These diodes are rated at 6 amps and 50 volts and will do just fine.


There are many ways you can accomplish this mod but I like things to be simple, clean, and easy. This walk through will show you how to do exactly that. I would suggest removing the negative from your battery but its not completely necessary. I like to check all circuits with a multimeter while working which cant be done without a battery. I know the correct wire colors for a 2013 so if you want to disconnect the battery than be safe, not sorry.

I wanted my head light LEDs to be on when the lower DRLs are on. Because of this I grabbed my power from the DRL circuit. I know some of you may want the LEDs to be on under different circumstance so this will be the variable. Accessing the DRLs can be done from many places however I chose to get it from the DRL itself because it was quick and easy. Pull your fender liners buy removing the FOUR plastic clips securing it to the fender.

Attachment 59487

Once the liner is out of the way you can remove the two 10mm nuts to allow the DRL to be removed from the front.

Attachment 59488

The 12 volt supply wire for MY 2013 BRZ is the white wire. I always solder and tape my wires, this ensure the connection will not fail due to vibrations (this is a car after all). Once you're done attaching a two foot 18-12 gauge wire to your DRL you can route the source wire up to your headlight.

Attachment 59489

Attachment 59490

I chose to make my attachment to the headlight side of this connection to keep it out of sight of Subaru service eyes. If it appears stock then most likely they will think its stock. I suggest you do the same however it can be difficult to access the wires (I have bigger hands so if I can accomplish this I'm sure many of you can as well). Remove the headlight connector and strip some of the heat shrink to reveal your headlight LED anode (positive). In my 2013 BRZ this wire is green.

Attachment 59491

I have read through a lot of posts about doing this mod and many of you have encountered a few issues. If you were to simply attach your 12 volt source wire to your green head light wire it turns on all the cars lights. There are many ways you can work around this but like I said, simple, clean, and easy. This is where your diodes will come into play. The image below will show you how to attach your diode into the green wire. you will have to cut this green wire and splice the diode into the circuit. The diode will allow current to travel from the lower DRL into your head lights LED anode powering the lights on at the same time. The diodes primary job is to stop the current from back feeding into your body harness eventually into some type of BCM which powers your running lights ect. Its very important that you splice the diode into the correct direction. Doing this wrong will cause the head light LEDs to not turn on at all. I highly suggest you solder the diode into place.Be aware that when soldering a diode you must "flash" solder. Transferring too much heat to the diode can damage it so wait till your iron is good and hot

when using a diode remember this, current will travel from black to silver but will not travel from silver to black. The diode below has a 6 amp threshold (more than enough for LEDs).

Attachment 59492

Once its all done it will hopefully look something like this.

Note that in this image it may look like my source wire is attached to the body harness side of the diode but I assure you its attached to the anode side of the diode

Attachment 59479

Once you're done secure your head light connection back to the head light and start on the other side! The picture below is the final product, looks stock to me!

Attachment 59482

Once the other side is done its time to sit back and enjoy the view!

Attachment 59480

I wanted to include a picture with the headlights fully turned on as well. This photo shows that when the head lights are turned on current travels through the diode and down to the lower DRL making them turn on. If this is what you desire (I did) then you're all done. If you want the lower DRLs to turn off once the head lights are on all you have to do (see picture below) is install another diode in your source wire(my red wire from the DRL). I'm sure a lot of you will have plenty of questions so please don't hesitate to ask. Congrats on a job done!

* follow this diagram if you wish for the DRLs to turn off when the HID headlights turn on (stock behavior). Thanks to @CIAGDDS for the great visual.
Attachment 59481

Excellent write-up, definitely going to do this once I get a full weekend and some time to myself.

nice job......just ebayed diodes! thanks for DIY.

Impressive. I was hoping someone would write a DIY on this for a very long time.

Sigh, I wish I had the electrical technician skills to do this, too scared of messing up since I've never soldered anything before :| looks like I'll have to take it to an auto shop and pay.

Also, do the DRL bars dim? I've heard that it might pose a blinding issue at night to other drivers.

..exactly which wire you must cut and re-wire with diode?

right electrical wiring? It's this way? your red wire goes to white 12+ DRL (soldered)?

^ This. The DRL, in my opinion are fairly bright when used alone (not bright enough to drive comfortably at night, but enough for you to see where you are going at low speeds). I thought I read somewhere that they were turned off by default when the headlights are on due to them being bright and not angled properly for night time driving. Then again, I could be completely wrong. I did get this info from the Internet after all :lol:

On topic, nice write up! :thumbup:

Good stuff, surprised it took this long for someone to write up a DIY! Thanks!

Well, Off to Radio Shack:)

Now can you figure out how to turn the front fog lights on without the main head lights?
(Using the turn stalk, when the ignition is on)
Thanks again for this DIY.

Don't Sweat it, if you take your time and follow the walk through you can do it. Dimming LEDs is possible but it requires the right components. When metering the DRL harness I got 14.5 volts. Its possible to lower the voltage via resistance and dim the LEDs but it depends on the factory Subaru LEDs. Someone should try it when doing this mod. I bet you can dim them slightly before they turn off all together. I doubt Subaru would use dimmable LEDs when they never intended to dim them.

you must cut the green wire located on your headlight harness.


that looks right, I assume the white mark is the silver side of the diode which is the side you want facing your headlight.

I wish I had fog lights to really dive into it. send me a pm and I can direct you in the right direction.

so if you want to NOT have the LEDs light up when the headlights turn on is this what you add to the added power wire?

http://i.imgur.com/8FBKgYU.jpg

On my FR-S, the LED DRLs dim when the headlights are turned on, so I agree, they would be too bright at night without dimming or turning off.