how to: full control of your fog lights

[oakrdrs187]

I knew about that law, no more than 4 driving lights on at once, which explains why manufacturers shut off fogs with high beams. But that othe fog only law is new to me.... not that I do it, I stopped doing that a long time ago when I saw more and more people do it. Especially since I di my bixenon retrofit I dont run the fogs period, the huge glare from them clashes with the clean projector light oncoming and on a wall.

[Corey2kG]

Oh ok I get it. My bad.

[Vince]

Wow thats nice and for 15$ only , I just installed some white hids into mine a day ago i like the look of the fog lights alot already.

[02_DSM]

what do you mean by full control

[finald8ta]

Complete control when you want your fogs turned on

Sent from my PC36100 using Tapatalk 2

[spdracr]

Fyi Nissan altima has the option where u could turn the fog on without the headlight. That's the only Japanese car I know of that has that feature.

[spdracr]

So since the trigger is the fog light switch. Can I wire it to the headlight switch so it would switch on when I turn my headlight?? Like reelax I also never turn my fog lights on without my headlights and I hate having to turn them on separately.

[wetamup2k3g]

^^I would rather leave them separate simply because the fogs don't need to be on in good weather. I find that they add too much to the foreground light right in front of the car, diminishing your distance vision because your eyes adjust to the brighter light right in front of you instead of adjusting to the light being thrown further away by your headlights. I plan on running foreground limiters in my retro just so I don't run into that problem with the HID's in the projectors.

Just my opinion, your car, your TR-7 install.

[spdracr]

I know what u mean. I still wanna hook it up to the headlight.

[wetamup2k3g]

It should work that way I think, I don't know though since the headlight wire is constant 12V going to the unit as long as the switch is in the "on" position, where the foglight switch is momentary and only sends a 12V pulse. Following that logic you don't even need that TR-7, just use a regular relay and hook the 86 terminal to the headlight switch, 85 terminal to ground, 87 terminal to foglight wire to the foglight relay, 30 terminal to fused battery 12V. I think that should work fine.

[spdracr]

It should work that way I think, I don't know though since the headlight wire is constant 12V going to the unit as long as the switch is in the "on" position, where the foglight switch is momentary and only sends a 12V pulse. Following that logic you don't even need that TR-7, just use a regular relay and hook the 86 terminal to the headlight switch, 85 terminal to ground, 87 terminal to foglight wire to the foglight relay, 30 terminal to fused battery 12V. I think that should work fine.

I'm not that good with figuring out wiring and relays and stuff. I'm good at following instructions. So if what u say will work for sure then I'll do that. Just need to make sure it's right.

[Corey2kG]

Dis what said switch does

N dis

[spdracr]

Looks good Corey but I definitely don't care much for just running fog lights alone.

So if u gurus can help me out I would totally appreciate it.

[wetamup2k3g]

According to the Haynes manual diagram I have in my hand right now, on the 8Ga the headlight switch gets its 12V from two fused wires; the red/black from the engine compartment gives power to the high/low beam portion and the black/white gives power to the parking/headlight portion of the switch. All the switch's outputs go directly to either the front ECU or the ETACS ECU. From there the front ECU provides the grounds for the control sides of the low- and high-beam relays, much like the PCM provides ground for the injectors. It's worse for the 8Gb; the low- and high-beam relays are inside the front ECU.

So if I were to wire the fogs to the headlights I'd use the actual headlight wires to power the relay for the fogs since I wouldn't want to mess with the ECU's at all. For your new relay to do what you want, I'd wire the 86 terminal to the actual low-beam wire on the headlight harness, 85 terminal to ground, 87 terminal to foglight wire to the factory foglight relay, 30 terminal to fused battery 12V. I gotta draw it out to see if you'd need a diode anywhere in there to prevent backfeeding anything, but so far I can't see you hurting anything.

[spdracr]

According to the Haynes manual diagram I have in my hand right now, on the 8Ga the headlight switch gets its 12V from two fused wires; the red/black from the engine compartment gives power to the high/low beam portion and the black/white gives power to the parking/headlight portion of the switch. All the switch's outputs go directly to either the front ECU or the ETACS ECU. From there the front ECU provides the grounds for the control sides of the low- and high-beam relays, much like the PCM provides ground for the injectors. It's worse for the 8Gb; the low- and high-beam relays are inside the front ECU.

So if I were to wire the fogs to the headlights I'd use the actual headlight wires to power the relay for the fogs since I wouldn't want to mess with the ECU's at all. For your new relay to do what you want, I'd wire the 86 terminal to the actual low-beam wire on the headlight harness, 85 terminal to ground, 87 terminal to foglight wire to the factory foglight relay, 30 terminal to fused battery 12V. I gotta draw it out to see if you'd need a diode anywhere in there to prevent backfeeding anything, but so far I can't see you hurting anything.

This sounds good to me. 87 goes to the relay black/white wire in the engine bay?? What size relay do I need?? Cuz I have spares from when I did the JDM headlight harness.

[wetamup2k3g]

Yep, 87 would go to the wire finald8ta spliced into in the engine bay for the factory foglight relay, the black/white. As for sizes, I haven't gone that far into it to know what sizes to use, but I'm guessing any relay that can handle headlight use should work perfectly for this.

[spdracr]

That makes 100% sense. Thanks

One more question. Ahuld I use one relay and wire it up under the steering column or should I should I used one relay tor each fog light and wore it up in the engine bay directly to the headlight harness??

[wetamup2k3g]

Hold on, I'm tracing out the wires now, and I think I told you something wrong about the wiring to the fog relay under the hood. Give me a few and I'll come up with a diagram that should get it straight.

Edit: Okay I got it, instead of hooking terminal 30 up to 12V, wire it to ground, since 87 and 30 have continuity once 86 is energized by the low-beam wire it's spliced into, and 87 is wired to the factory foglight relay which is should be terminal 85 on that relay, not 30 like I thought it was. The Haynes has no terminal markings, you just have to follow the wires. So on your new relay, wire terminal 30 to ground as well as 85, 86 to the lowbeam wire and 87 to the factory fog. Good to go. Hope this helps bro!

Second edit: the one relay should be fine, in fact you can install it somewhere under the hood since it never has to come near any of the switches.

[spdracr]

No problem. Take your time.

[wetamup2k3g]

So here's the diagram:

SpdracrWiring by wetamup2001, on Flickr

And here the Haynes diagram I've been working from:

HeadlightWiring8Ga by wetamup2001, on Flickr

Click the links to get the pics as big as you need them. Hope this helps!