Well a lot of people have been asking how to install fogs on a non-prewired MR-2 (most likely a 91) and so I thought a write up was needed
First: to verify you do not have the wiring harness, look in the main fuse box under the hood and look for the location of where the fogs relay would be. You can also look in the gap where the fog lights should sit and if you find a wire harness that is tied back, then you are prewired. Same goes if you find a wire tucked up under the dash where the switch goes. If there are wire connectors in the location, you are prewired and you have a lot less to worry about.
I am working with a 1991 N/A
Materials to buy:
-Relay and connector
-roll of 16-gauge or thicker wire
-10 female wire connectors
-4 male wire connectors
-Switch, OEM or aftermarket (84160-17030)
left bracket (52126-17010)
right bracket (52125-17010)
clip (90467-14038) – You’ll need 2 of these, one for each bracket.
(part numbers courtesy of Gsus in this thread )
1.) You will need to either find a generic fog light relay kit or make your own. you can buy relays at any auto parts store with the connector.
Once you have the relay, split out several feet of wire so that you only have a single wire instead of two tied together, unless you bought single strand wire
On four long pieces of wire, strip about a 1/4 inch of insulation off and connect a female connector on each end. Make sure that the female connectors fit correctly on the relay.
If you cannot find a relay that does not have a socket to fit into, dont worry. The female connects fit snugly on the relay, for it is meant to be connected that way. If you do have the socket, the female connectors fit into the socket, but you will have to bent the back of the connector where there are slots cut into the connector. This will allow the connectors to grab into the socket and not be pushed out when you push in the relay.
Each slot in the relay has a specific location that needs to be wired correctly. The following pictures show what the relay socket looks like and a wiring diagram to decipher the locations of the relay
Please mind my crude wiring diagram
The middle slot is unused in this application
*I am not sure of the correct terminology for the connector of the relay so i will refer to it as the relay socket*
2.) once you have four wires connected to the relay socket, roughly lay out the wires to the desired locations.
The switch is easiest to keep as a double bundled wire (like a stereo system wire) because you will need to run one wire through the firewall to the switch, then back through to the corner light.
Alternatives to wiring to corner light: If for some reason you would like to have the fogs on without any other lights on, wire up the signal wire (switch wire) to the switch, then to the cigarette lighter. The lights will turn off when the car is off, but you will have to manually turn them on/off if you do not wish for them to be on during the day
*the signal/switch wire is not used to provide power to the fogs, but as a voltage source to kick the relay on. The relay opens up power directly from the battery*
*i am locating the relay in the frunk if you havent already figured that out*
The chassis ground will connect to any non-painted bolt on the chassis. I used the bolt connecting the front sway bar
The BATT. (+) wire will connect directly to the battery
*I did not realize until I am doing this write up, but it is wise to buy an in-line fuse to put between the battery and the relay– this will prevent blowing your relay or perhaps worse
The remaining wire is the positive wire for the fogs
This wire was fished through the rubber coupling behind the front left headlight and run under the headlight to the location of the left fog light
Split the positive fog wire into two to run to the right fog light.
Connect the positive fog light wire to the red wire on the left fog light. Then run the other positive wire to the red wire of the right fog light
The black wires on the fog lights will be wired to a chassis ground, so find a good place to ground these wires. I ran the wires back up to the same place I grounded the relay
3.) Now your fog lights are all wired up to the relay and you need to wire the switch and signal wire. Run the signal wire through the firewall. I used a hole that is located by your feet in between the brake and clutch iirc.
Depending on what switch you are using, test the wires to find the two wires that have no continuity in the off position and full continuity in the on position. If you are using an aftermarket switch that has a light in it, on of the 3 connectors on the switch is the ground. The switch will not light up if you do not ground it. The ground is most likely labeled, but if not, it is usually one of the outside connectors, not the middle one.
Now run the outgoing wire of the switch back through the firewall to the positive terminal of the corner light.
*Make sure you do not connect the signal wire to the turn signal. You do not want to look like a fool making a left turn and your fog lights are flashing with the turn signals*
Once you have all the wires connected, make sure the relay in engaging. You will head a click in the relay when it is connected correctly
3.) To mount the fogs, cut the farthest horizontal grill piece, but do not cut it too close to the first vertical piece. Leave about a 1/4 inch so that the fogs can cover up that rough edge.
I am not too entirely sure what most people are talking about when they mention a mounting bracket, bc my jdm fogs did not appear to have a detachable bracket and mounted fine to the stock location.
*update* I have been informed later in this thread that the brakets are used as a way to anchor the lower part of the foglight so that it aims downward so you do not have to aim the foglights like i have explained later in this post
To install the bracket, i assume there is a single bolt that holds it on–i have not installed this bracket so someone please inform me if there is a different way to attach this
Here is the bracket:
the clips are pushed into the hole in the bracket–one clip is used per side–a post on the foglight is meant to pop right into the clip
The bolts needed to mount the fogs are two 8mm bolts for each fog, iirc. i used extra bolts that hold on the radio, for they are the correct size/pitch
(you can find these at any junkyard with toyotas, they are usually just sitting on the floor of the car if the radio has been removed)
after they are mounted, make sure they are level and not aimed into peoples eyes. There is a small phillips head screw on the face of the fogs that when tightened, raises the fogs and vice versus. I faced my car towards a closed garage door and just took a roman measurement (distance from elbow to tip of finger, for example) from the headlights to the fogs and made sure that the light pattern was the same distance on the garage door. This will ensure that the angle of the fogs is the same as the headlights. This may be an incorrect way to aim fogs, but it works for me.
Other half-_____ option:
Instead of worrying about the whole relay confusion, it is possible to just hard-wire the fogs directly to the corner lights. Again, make sure you wire them to the parking lights and not the turn signals. I strongly suggest you take the time to wire the relays bc it will be more reliable and not stressing your electrical system. You run the risk of blowing fuses if you wire them directly to the corner lights.
I hope I have not forgotten anything, but if I have, please feel free to PM me and I will edit the thread. Please do not post any mistakes I have because I would like to keep this thread easy to read.
Hopefully this will help people. I will update the thread or make another with how to install the motorized JDM fogs once I get the steering wheel sensor.
This documentation in no way replaces the Toyota MR2 Repair Manuals. The purpose of this content is only to provide supplementary information to fellow MR2 enthusiasts. Midship Runabout and its contributing authors will not be held responsible for any injury or damages that may occur as the result of practicing any of the methods or procedures described within this website. Article and photo submissions are property of the contributing author.
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