DIY JDM foglight "turn assist" circuit.

[TbirdMan]

Well, i wasn't satisfied with just wiring the "turn assist" lights in my JDM fogs to the fog light circuit. I wanted to have them behave like the real JDM lights do. However, as anyone who has studied the problem knows, out turn signal circuit just isn't setup to do that. this is a simple circuit that converts the flashing voltage source of the turn signal into a steady +12V.

Ok, after consulting with some very knowledgeable folks at http://www.electronicspoint.com, here is what I have come up with. to make two of these boards you will need:
2x 1.75in breadboard (2x in RS#276-148)------------------------------$1.99
4x Diodes (2x in RS#1N4001) 0.99x2= ---------------------------------$1.98
2x 470uf 35V Electrolytic Capacitor (5x in RS#272-1030) 1.49x2 -$2.98
2x 2200 Ohm Resistor (5x in RS#271-1121) ---------------------------$0.99
2x 470 Ohm resistor (5x in RS#271-1133) -----------------------------$0.99
2x 2N2222 NPN Transistor (5x in RS#276-1617) ----------------------$2.99
2x OMRON 12088567 relay -------------------------------------9.99x2-$19.98(you can save some money here by looking in the JY for late model GM's)
Total-------------------------------------------------------------------------$31.90

plus an enclosure and some kind of wires or plugs to wire into your harness.

A note on this circuit, I am not an electronics expert, I a not really even an amateur. I did not design this 100% It was a collaboration with a couple of gurus on an electronics forum, as such, I cannot really help you if you change the specs. No guarantees are given or implied. do this mod at your own risk. any modification to your vehicles lighting system has the possibility to run afoul of regulations. if you do not know how to solder or read schematics consult with someone who does.


+12V line could come from your headlights, fog-lights, or really any source, just be sure it can handle the added load of the 1156 bulb.
Signal line is your turn signal line.
and the ground can come from anywhere.
https://sl-i.net/FORUM/images/imported/2011/04/TDC3-1.png
this circuit turns on as soon as the signal receives 12V and turns off about 1sec later. any changes to any parts may affect this operation.

If you want to adjust the hold time, you can either swap the 2200 Ohm for another resistor, no less than 470 Ohm or you will let the magic smoke out of your transistor and no more than about 5k Ohm or you wont have enough current to drive the base, or you could change the capacitor out for a smaller one for less hold or larger for more.

I may do a writeup if you feel you need it, but as I said, if you don't feel confident you can translate these schematics into a working circuit board, you may want to find someone who does.

[TbirdMan]

Thought I would go ahead and throw up some pics of my completed boards, I have tested them, but have yet to install.
https://sl-i.net/FORUM/images/imported/2011/04/0423110252a-1.jpg
https://sl-i.net/FORUM/images/imported/2011/04/0423110253a-1.jpg
https://sl-i.net/FORUM/images/imported/2011/04/0423110253b-1.jpg
https://sl-i.net/FORUM/images/imported/2011/04/0423110254a-1.jpg

[Legacy89]

I was thinking about this, the easy way out is the Hella Dynaview Evo2.
Tough this seems like a nice way to do it cheaper.
Props to you guys.

[TbirdMan]

you could also combine the two boards into one and have basically the hella system. this just seems easier cause you can just tap into the wires at the lights and put a box behind each headlight.

[Legacy89]

Yeah, with high enough capacity it will even run the fogs at 55w. Tough i dropped the entire idea, im going to use the JDM fogs from BD/BG on my BE once i get a new front bumper. And then i will put 6000K 35w hid in the projector and modify a 15w 6000K bulb for the sides.

[TbirdMan]

this circuit is for the side lights of the on the BD/BG JDM fogs. I would strongly suggest not putting any kind of HID in them. they are not designed for them and i have seen at least one case where a guy melted the plastic where the light mounts even on the projectors.

[Legacy89]

Should be fine, im going with the lowest wattage and we rarely see temperatures above 18C here.

[TbirdMan]

Do what you like, I am just telling you what I have seen.

[Soul Shinobi]

Hate to be a bother, but no one has explicitly said what this actually does!

[TbirdMan]

ok, the JDM second gen legacies fog lights like this: https://sl-i.net/FORUM/images/imported/2011/05/P1120100-1.jpg
Have two bulbs. one for the main fog light, and the secondary ones are aimed to the side of the road. in the JDM version, one light comes on when you put your turn signal on. our cars can't do this because they are wired differently. (not really sure how JDM's do it) in order to make them work I either had to totally rework how my turn signal system works, or make this circuit. what it does is use the flashing 12V signal from the turn signals to activate the secondary lights only on the side you are turning.

[Soul Shinobi]

Thanks. :grin: I had a feeling it was something like that, but no one had said it outright.

[HeresMyMind]

I just wired the outside lights as running lights, that way they are always lighting the sides better :-D

-B

[TbirdMan]

I was gonna do that, but i kinda wanted a project and i wanted to do something different.

[r3v_v3ng3]

great write up. i did the lazy way and just have them on whenever it sees ignition but couldn't you run two relays (one of each signal light) and use the the blinker light as a trigger for it to light up and flash?

[grayguy]

^that idea seems a lot easier than the other way.

[chuckthefuk]

Very cool .. I always wanted to rig up my old jdm fogs to do this but why so much wiring>?

Why not just a simple relay tapped into the turn signal and a steady 12v to power the fogs when the relay is triggered?\

From what I have seen the turn signal only gives out 12v when the indicator is active.
-Chuck

[Soul Shinobi]

From what I have seen the turn signal only gives out 12v when the indicator is active.
-Chuck
Well that should do the trick shouldn't it :razz: Maybe I'll just have to get some JDM fogs.

[Wagaru]

the capacitor keeps the relay "alive" between flashes. it really is a 2-3 second delay circuit so that the light doesn't flash. it will also stay on a few seconds after the blinker's last flash. is that omiron relay a 5v control? that would explain that.

[phi11]

Can I request a video of this please?
Just the flashing part.
I really want to do this.

[TbirdMan]

sorry for the long delay, I am gonna try to get this mod done soon, my mom has been using my car for the summer. I will try to get a video of it in action soon. the capacitor is holding a transistor closed, the transistor is controlling the relay, the relay is a 12V control. I tried to control the relay with the cap, but it would have required a larger cap. and this way, it doesn't matter what 12v relay you use, the delay will be the same.

[camroncamera]

BUMP

Is the following correct for stock behavior of JDM foglights on JDM vehicles -
Foglight swtich is OFF: When turn signal indicator is activated, the outer non-projector foglight on that side lights up CONSTANT ON (until the turn signal is deactivated, and then the foglight turns OFF)?
Foglight switch is ON: When turn signal indicator is activated, there is NO CHANGE to the foglight and it stays CONSTANT ON, as it is already ON?

[Dead91silvia]

Yamazaki took vid of how they work... I'm opting out of doing this part JDM. I want to turn them on when I want, but this is a cool DIY...

[camroncamera]

Yamazaki took vid of how they work... I'm opting out of doing this part JDM. I want to turn them on when I want, but this is a cool DIY...
I think I'm in agreement with you about control of auxiliary lights. I don't know for sure what I'll be doing about switches when I install the JDM Limited bumper with all of its foglights, but I think I'm going to relay everything if possible. Like you, I don't have any blanks in the dash to add another OEM foglight switch, and I'm not too keen about drilling into the dash to add non-OEM switches all over. I think I've read that the USDM foglight wiring connector is a direct fit to the JDM projector foglights, can you confirm this? And if that is the case, does the one USDM foglight switch light up both the outer (flood) and the inner (projector) bulbs at one time? Seems funny to me, as the projector foglight harnesses have a 3-wire connector. The Limited foglights use a 2-wire connector, maybe that is what is the direct fit to the USDM harness?

EDIT: I think it must be the big round fogs that fit the USDM harness:

I got the big rounds plugged into the stock USDM LGT fog harness, so those are not a problem. I was going to use a the JDM Fog selector switch, but I have a feeling it's not going to work like I want it to. I want to be able to run ALL the fogs at the same time! I will be using the mod that someone posted before about using the fogs with high beams also, but thats later. I want all these light to be as bright as they can without over loading.

[Yamazaki]

Video when my wife had the GT-B limited:
https://sl-i.net/FORUM/images/imported/2012/03/th_DSCF2190-1.jpg (http://s426.photobucket.com/albums/pp350/yamazakisubaru/car%20parts%20accessories/Other%20projects/?action=view&current=DSCF2190.mp4)

You can't have both sets of fogs on at the same time and the corner lights ONLY come on when both the headlights are on AND the turn signal is on.

Which I think is all pretty lame.

[camroncamera]

Video when my wife had the GT-B limited:
You can't have both sets of fogs on at the same time and the corner lights ONLY come on when both the headlights are on AND the turn signal is on.
Which I think is all pretty lame.
Thanks Yamazaki, that really clears up the stock JDM behavior for me! :smt023

[maddoc]

Video when my wife had the GT-B limited:
You can't have both sets of fogs on at the same time and the corner lights ONLY come on when both the headlights are on AND the turn signal is on.

Which I think is all pretty lame.
Definitely rewiring all the fogs on my JDM GTB bumper to be independent of one another...debating on wiring the "turn assist" for another use

[kiyo1990]

I may try this..but not electrically secure with my self