INTRODUCTION

This is my experience / tutorial trying (and eventually succeeding) to wire up OEM foglights to an OEM harness and switch on a 2004 OZ Rally edition Lancer. From what I’ve read, most of what I detail below should be transferable to any 2002 to 2007 ES / OZ / Ralliart.

Lucky for you, it seems that all Lancers are wired to have foglights from the factory, even if Mitsubishi doesn’t actually install them. This guide will run you through getting them set up. Alternatively, if you have some aftermarket foglights, this will help you identify what you need to do to set them up without running a “new” switch or completely bypassing the existing wiring that’s already there.

I was a bit frustrated that everyone did these aftermarket installs and guides when 95% of the work was already done for you and you didn't need to run any extra wires. If I knew the stuff that was in this thread from the get-go it wouldn't have taken me a two weeks to piece it all together. So, for your benefit, here it is.

GETTING STARTED

Here are a few things you should check before going out and buying parts:

1.Check for the OEM wiring harness plug for your fog lights. It is in the centre of your bumper underneath your car (See the below image). If it was anythng like mine, it will be covered in road dirt. Take a minute to clean that off thoroughly.


Stock location of connector in front bumper (left, black cable) and connector (right, upper piece)

2.Undo the two screws in the gauge surround and pop it off, take out the left dash trim panel and check for the fog light connector. On my vehicle it was “plugged in” to the plastic and went nowhere. It is to the left of the power mirror. There are two screws you remove to take off the dash surround and it should pop out. You should then be able to firmly pry off the small dash piece

3. Check the engine fuse box. Consult the diagram on the fuse box lid. The fog light relay is the forward-most relay in the box. Look in the holes for the relay pins and ensure that there are metal bits in there. That will confirm that your fuse box is wired up to have foglights. If those are missing, you will need to add wires to the wiring harness. I won’t be covering that. Same goes for the foglight fuse itself. My vehicle had a fog light fuse in place even though it didn’t have foglights. It’s a 15A fuse in one of the forwardmost positions in the fuse box. Consult the fuse box lid.



Alright, have you got your 3 bases covered? Good, then we can move on to…

THE PARTS

You will need:

An OEM switch OR a 4-wire illuminated momentary push-button switch (if you want to do this properly)

A two-wire latching switch (ie, flip it and it completes a circuit and stays on) (if you want to do this with your aftermarket fog light switch)

One of the relays that fits into the engine fuse box (MR538851, 12V 20A relay)

The front bumper cover wiring harness

The fog light assemblies

(optional) Dash trim piece from the Ralliart or Evo with button cutout (will make switch install easier)

A screwdriver

A pair of needlenose pliers

A weekend (maybe like an hour and a half if you’re not an idiot like I was)



If you want to do this the easiest way possible, find a bumper from a Ralliart as well as the dash trim panel, and either steal the parts inside the front bumper cover from it or swap it onto your car.



THE PROCESS

RELOCATING THE SWITCH

This part is not necessary if you will be replacing your dash trim piece with one that has a button cutout. I didn’t want to do this out of pure spite so I relocated the button to the blank one next to the gauge dimmer switch. If you do have a trim piece with a cutout, simply unplug your power mirrors and the blank foglight switch and plug in your replacement piece, then skip to the relay fuse section.

If you took apart your dash as part of your preliminary checks, you can start by following the fog light connector wiring harness back to where it meets the wiring harness for the power mirrors or the main instrument cluster wiring harness. You will probably need to unscrew your gauge cluster (three screws) and jiggle it out of the way to get some working room. If you want, unplug the two connectors on the back of the gauge cluster and remove the gauge cluster completely.

On my vehicle, the wiring harnesses were wrapped in foam, and under the foam, tape.

VERY CAREFULLY cut away at the tape to separate the power mirror wiring from the wiring for the fog lights. If you wanted to be extra safe, disconnect the battery before doing this. If you go back far enough, this should give you enough room to route the connector down past the driver side vent and into position behind the dimmer switch. It will take some maneuvering but I believe this is the shortest route.




Route for the foglight switch around the driver's side vent (left) Location of the power mirror and foglight switch wiring harness in dash (right)

If you don’t want to work upside down, I also recommend opening your door and gently prying off the side dash panel. This will give you access to grab the connector from the side and plug it in to the switch.

You can remove the blank button by pinching the sides and depressing the clip and sliding it out towards the firewall.

If you have the OEM foglight switch, pass it under the left side of the dash and slide it in through the back. Mine did not quite click into place here, so you may have to finaggle something to get the switch to stay perpendicular. If it’s off, even by a little bit, the button will “stick” and you won’t be able to press it properly. I used some electrical tape to keep it centred.


Lastly, connect the switch to the foglight connector. If all your parts are the OEM parts, that’s all that needs to be done here.


Foglight connector (white) plugged in to foglight switch (black)


If you want to do the wiring yourself (say, for a switch that came in an aftermarket kit), see the below diagrams for some guidance. The RED and BLACK wires (pins 1 and 2 on the connector, the bottom) are the ones which take a momentary “short” to tell the computer to turn on/off the foglights. BLACK with YELLOW stripe is ground, and GREEN with WHITE stripe is the power for the instrument lighting (what will cause your switch to glow in the dark).



Switch diagram (left) Connector pinout (right)

INSTALLING THE RELAY AND FUSE

In your engine compartment, install the relay into slot A-04X (A06X on an Evo I believe) — front-most slot, with the arrow pointing towards the passenger side of the car. You can use any of the MR53881 relays there to test. If you have an aftermarket or generic switch, refer to the below diagram for the pinout. Make sure that the 12V, ground, and trigger pins are correct or you might burn something out in your front-ECU.




Install the fuse into the front-most mini slot in the fuse compartment. This should be listed on the lid of your fuse box. If it’s already there, check that it’s not burnt out for whatever reason.



INSTALLING THE FOGLIGHTS

First step is to remove the bumper cover. There were 5 front grille styles for this car so I can’t give you the full list of steps, but assuming it is mostly the same, you will need to remove clips up top from under the hood, clips from the wheelwells, and two clips that you will need needlenose pliers to grab the tabs and another hand to pull out from underneath on the frame.

There will also be four bolts, two going into each fender and two that go into the bumper support from top down.

Once everything’s off, gently wriggle the bumper and scoot it over to where you can work on it.

Stock bumpers will have plastic “air deflectors” where the foglights should go. You can undo four screws on each and remove them. Installing your new foglights is simply a matter of screwing them in to the same four holes. There should be holes all along the inside of the bumper to route the foglight harness. You can remove the clips for these by grabbing the sides with needlenose pliers and gently wriggling them backward with your free hand.

Once the harness is routed to each foglight and plugged in, move the bumper assembly back into place on the car and temporarily hoist it up onto the bumper supports. You should be able to take the centre connector on the bumper and connect it to the one that goes to the rest of the car. Again, if it is dirty, clean it, or you will not be able to get a good connection or plug the connector all the way in.

If you have an aftermarket fog light kit, that bumper connector is where you should probably wire in to the 12V power so that you can use the OEM wiring. It’ll save you from having to run extra wires or splice in to other systems. If you can, get one of those light connectors and solder in to that so that your foglights will be easy to remove if needed.

At this point, before you put stuff back together, do a test. However you’ve got that switch wired up, pin 1 of the front-ECU is expecting you to “blip” it on for a moment to turn on the lights. You’re basically politely asking the car’s computer to turn on the lights for you. When you press the button again, you’re asking the computer to turn it off. The computer switches the voltage on pin 3 of relay A-04X based on what the RED and BLACK wires in the dash are telling it to do. Leave it on, it does nothing. Leave it off, it does nothing. Turn it on and off rapidly, the computer goes “oh the driver pressed the fog light button” and then turns the fog lights on for you. What I’m getting at here is that the button in the dash is not directly connected to the circuit that is powering your foglights. This is different from most aftermarket kits where your lights will bypass the computer completely, going straight into the 12V from your battery.

Once you’re sure they’re working, reverse your process for taking off the bumper, put the dash back together, and you should be good to go.



If you have any questions or would like more detail, post in the thread and I will edit the OP with anything else that comes up.