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2005 Mustang V6 fog light wiring harness guide?

2894 Views 5 Replies 6 Participants Last post by  nanesnj84
I've been searching high and low on the internet and on this forum for a guide I could use to assist me installing a wiring harness for fog lights but have come up short with results. Does anyone have a guide that they wouldn't mind sharing? Even if it's not exact to what I have it'll still help me in the long run. I would greatly appreciate it! Thanks in advance!!
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I went with all oem pieces to add foglights to my car. I will provide a list you will need to make them work.
Gt fowardlamp harness
Headlamp switch with fog
Add relay and fuse to the relay center under the hood
Have your sjb programed for foglights.Or get one from a Gt at the salvage yard
Easy way to do this

I went round and round looking for data so I made up a guide so others wouldn't have to go through what I did. Thus I am spreading the information on old posts, forgive me, for people using the search feature or coming in through Google search. This is also relatively cheap.
I put a pony package grille in mine (got it at Carlisle Car Show for $45) came with no lights, so I got some off of eBay for $30 clear lenses. Came with a harness and no directions.
I bought a GT headlight switch (mine was a base model with nothing special) off of eBay for $30, went to Autozone and got a generic Bosch style 4/5 pin relay, and here is what I did...

First disconnect your battery.......................
On a Bosch style 4/5 pin relay, do this;
Pin 30 and 86 slice together and run wires to your +12 volt source (fuse box bolt) and put a fuse between the splice and the power source.
Pin 87 run a wire to the (+) side of your fog lights.
Pin 85 run a wire from here to inside your car. If you have a headlight switch with fog option, great, if not get one.
Pop out your headlight switch. Use something thin and flat (knife, screwdriver, what have you. Just don't mar up you dash).
Once out, you will see two harnesses. One black and one gray. Disconnect them both if you are replacing the non-fog headlight switch with one that has fog light capability switch, otherwise just the gray harness.
On the gray harness, look for the orange wire with light green trace. (only one on the harness, its in a corner) Cut it 3-5 inches back.
On the car side of the cut wire, tape it up and secure it out of the way.
On the harness/switch side, connect the wire you ran into the car to the orange wire with light green trace. Solder/crimp connect and insulate.
Ground the (-) side of your fog lights to the frame/body.

You should test it all before popping the switch into the dash. You should have lights when you pull out on the switch with parking lights on.
This is called a ground trigger relay setup. Your switch, when on fog, grounds the circuit and activates the lights.
I also have a quick relay diagram if anyone needs it.

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So for clearity, this mod bypasses the SJB all together making it unnesessary to have the SJB reprogrammed? Cool. I've often wondered why they felt the need to have a chip control what options are available. Either the option s phisically there or it isn't, why require the reprogramming of a chip if it doesn't interfer with the actual engine/smog requirements of the car?
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I decided to avoid the original wiring in my 2007. Since I am a novice, I wanted to avoid causing problems in my SBJ panel or other electrical problems - can be very costly to repair. Some of the other posters appear to be more proficient in their electrical skills.
I installed a wiring harness for fog lights, purchased on ebay for about $15. It had all the connection for attaching fog lights, a switch for inside the car and a relay. I added a fuse between the relay and the battery. I installed a switch between the relay and the power wire behind the radio. (When I turn off the ignition, the fog lights go off - prevents a drained battery in case I forget to turn off the fog lights.) You can use the information posted by Ghostrider2K, to determine how to wire the relay. Also, most wiring harnesses come with instructions, and there is lots of information on the internet on how to wire your harness. Good luck with your project.
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I need help...
I followed all instructions. however when the headlight switch does not turn on the fogs. I though it was a bad switch I went and got another switch and still doesn't work. i hooked up an after market witch and fog turn on no problem. When i probe tested both switches there is not +12v coming out of the org/grn wire. is there a fuse or something. Or btw i have an 05 base model.
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