Donate to the Forums
View unanswered posts | View active topics It is currently July 13 2020, 2:03 PM

Reply to topic  [ 3 posts ] 
 Rear Fog Light Wiring For A-Spec Mx-3's. 
Author Message
Senior Member
User avatar

Joined: May 25 2002, 2:01 AM
Posts: 11212
Location: CFB Val-Cartier, Quebec, Canada
Reply with quote
Post Rear Fog Light Wiring For A-Spec Mx-3's.
For those that aren't aware of it, Mx-3's overseas (Europe, Japan, etc) have an option for a rear fog light in their Mx-3. I believe this is something that's typically in Europe since most European cars that I'm aware of have this option. I have a co-worker with a Jetta who put in rear fogs just by inserting bulbs into the empty sockets and getting a e-spec multi-function light switch from Europe with the rear fog option. Unfortunately ours aren't that easy, but it's not hard at all.

As well, it seems some local cars have a perma-quasi-fog light as part of their running lights. I was driving back in the rain and noticed a Volvo wagon with this one light on the drivers side that was brighter than the others. It was this misty rain in the afternoon so visibility was poor, but because of that one light, his car stood out and I could see him better, him being 2 cars ahead, than I could the cars right in front of me. That's literally what inspired me to do this mod. Yes it does add that little extra JDM to my car, but you can't complain about added safety in terms of being more visible to other drivers

If you've never seen them, you'll notice that overseas Mx-3's use only the outter lights in the tails for running lights and brakes. The inner lights are not used at all for running or brake lights, and only the driver side is the rear fog light. There's a discussion about it in this thread:

Here's what we know as our North American tail lights:
(I'm stealing your pics Duncan ;))

E-Spec tail lights:

E-Spec lights with Altezza housings.

One thing that has been noticed is the shape of emitted light on the stock tail light. The E-Spec lights look square. My personal theory is that they use a different housing so that the lights don't "bleed" between each other since the inner and outter lights work independantly. I'm not sure how this mod would look on stock lenses, but with Altezza's no problem.

As for the mod, I did a type of hybrid setup. I integrated the "fog light" but it doesn't affect the regular function of that light when not it use. I didn't go "true JDM" and disabled the inner lights completely. I figured, I've got 4 lights, might as well use them. And if i'm integrating the fog light for visibility, 4 lights are better than 2 after all. For those who want to do this, I'll give a few options at the end .

When you take off the lights, for the wiring (yes, I labelled the sockets, just in case, I dont want to get cut-happy and snip the wrong one), the bulb has 3 wires running to it:

Black - Ground
Red - Running Light Element
Green - Brake Light Element


The way I have it wired up, the fog light will only be able to be turned on when the running lights are onn; kinda weird otherwise and my front fogs are wired up that way too. In the end, it actually simplified the wiring since I have wiring for the running lights right there.

Here's the wiring diagram for this setup. The only thing I was skeptical about is that you *have to* cut the green wire, not a fan of cutting stock harnesses, but it is easilly fixable if you want to revert back.

I used all 14 guage wire since we have an abundance of that at the shop and it's just slightly higher guage than the stock harness, so it'll be plenty. The red jumper wire between 86 and 87 for the relay doesn't need to be nearly that large, that's just for the coil of the relay and draws only around 160mA, but again, we have plenty, so why not?

Here you'll see I extended the green wire from the bulb. You need to since it's much perfered to have the relay inside the car than outside. The red for the running lights, I just tapped into with a self-tapping terminal and ran the yellow wire back into the car as well. That yellow wire will power the relay and the fog light.


Here you'll see I extended the green wire from the harness. I used white to change it up so i knew what is what. You'll need this wire if you want your brake lights to still work on that light when the fog light isn't on.


That's it for that part, just organized the wires and next is to wire up the relay.


Here you'll see the wiring for the relay. There's 2 discrepancies compared to my diagram. The white wire connects to the terminal 87A, the center terminal in the relay. In the diagram it's still green, but it was green in the harness, so I kept it consistant for the diagram. The second yellow wire with the black tape is the ground, which is black in the diagram. I wasn't "borrowing" a long piece of black wire, we had a long length of yellow in the scrap bin, so i used that, and plus it'll be easy to identify under my dash.


From there, run the ground wire to wherever you want your switch to be. I got a fog light switch from a Escort GT and used the empty space in the center console, even the logo faces the right direction for rear fog light, just that the line are going up instead of down, but close enough.

This is a ground-switched circuit, so I connected the ground from the relay to the switch, and another wire from the switch to the chassis ground.

And some pics of it completed:

No Lights:

Running Lights:

Running Lights w/Fog Light On:

And at night:
Just the running lights:

Running lights with fog

Now, you can change this up a bit if you want. Some cars have apparently 2 rear fog lights. My co-worker's Jetta has 2 actually. So if you want to have 2, just repeat the same process on the passenger-inner light, connect both ground wires from the relay's together into 1 wire and run that single wire to the swtich.

If you want to do true "JDM/EDM style", it's easier. For the passenger inner light, just take out the bulb. For the driver's side, that green wire I extended with the white wire, just don't extend it. Seal up the cut wire so it doesn't short out anywhere. For the red wire that I tapped into with the blue self-tapping terminal, instead of tapping it, cut it and splice both harness red and the yellow wire together; that yellow wire still needs to go to the relay. The red wire left loose on the bulb, seal/tape that up just to protect it.

You can even do a 2 fog/JDM hybrid setup by following both the above steps on each inner lights. Your call really..

So have fun and be creative :)

1992 Mazda Mx-3 GSR - 2.5L KLZE : Award Winning Show Car & Race Car ['02-'09] (Retired)
2004 Mazda RX-8 GT - Renesis Wankel : LS3 Coils, BHR Mid-Pipe + Falken RT-615K 245/40r18
2011 Mazda Mazda2 GS - 1.5L Manual : Yozora Edition (1 of 500)
2003 Nissan Xterra SE - 4x4 Supercharged : 2" Body Lift, 4" Suspension Lift & 33" MTR Kevlar
2001 Nissan Frontier SE - The Frontrailer : Expedition/Off-Road Trailer Project

July 29 2007, 12:17 PM
Profile ICQ WWW
Forum Moderator
User avatar

Joined: August 10 2005, 10:08 PM
Posts: 6128
Location: Hillsboro, OR
Reply with quote
Thanks Mike, for posting this info... I will definately be using it once I acquire my euro tail lights! I'll post up pics when I do!

My Feedback
92 mx-3 gs klze 'race car' IP 15.05 @ 92.5mph
92 mx-3 gs klze 'daily driver' IP 14.55 @ 95.7mph

August 10 2007, 12:30 PM
Profile WWW
Site Administrator
User avatar

Joined: November 07 2000, 3:01 AM
Posts: 8391
Location: Lat 35.1N Lon -90W
Reply with quote
Moved to the FAQ!!! Nice write-up

Keep this site alive! Donate!

August 10 2007, 12:40 PM
Profile WWW
Display posts from previous:  Sort by  
Reply to topic   [ 3 posts ] 

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.