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After Market Fog Lights into Factory Wiring

76K views 37 replies 24 participants last post by  steves92 
#1 ·
I bought my 2006 Wrangler without factory fog lights. Shortly after, I bought some KC lights and wanted to throw them on. I did a sloppy but functional job.
Recently while poking around under my fenders I found that my jeep was wired for factory lights. I decided to remove my sloppy wiring job and tap into the factory wires. After searching on the interet I found a lot of people had the same questions but the answers were scattered and lacked detail. So after 4 hours of tracing/testing wires I found the answers I was looking for and have decided to share. I hope this is helpful to anyone with the same questions I had.

The open connection points I found [one under each fender - near side marker lights] White/Orange wire comes from the fog light relay and the black is a ground.



Then I looked into my fuse box and saw I was missing the Fog Light relay [35] but did have the fuse [19][Under Hood forward of Battery]



I spent some time and investigated these relay and fuse slots.



I traced two wires to the steering column, the white/yellow wire from the fog lamp relay [slot 35] and a red/green wire from the fog lamp fuse [slot 19] - After taking apart the plastic that surrounds the column I found these wires leading into a large plastic clip located behind the hazard light switch.



I removed the two wires related to fog lights and hooked them up to a rocker toggle switch. The Red/Green wire comes from the Fog Light Fuse mentioned above and brings power to the switch and the White/Yellow wire brings power from the switch to the Fog Light Relay [See relay image above - note where the white/yellow wire enters the relay housing.]

*Be careful at this point as there are a couple of wires entering this clip with very similar colors. Notice on my picture I am choosing the white/yellow paired with the red/green. These two wires are located next to each other and one space away from the white/green and green/white [hi beam] wires. There is another wire on the "top" of this clip that is cream/gold colored and looks very much like the white and yellow.



And heres my toggle mounted on the dash behind my light control stick. [Please ignore the dirt] Toggle has three wires - ground - power in [red/green] - power out [white/yellow]



I was surprised to see that my instrument panel now illuminates a green fog light icon in the top left when I turn my fog lights on. I also now have the often bypassed feature [thanks to my fog light relay] of not being able to use my fog lights while hi beams are active. We'll see how long I keep this feature before bypassing it.

Let me know if there are any questions, or if you forsee any problems with this set up. I hope this information is helpful.

[Note: The same relay can be used that is found in the Starter, Fuel Pump and Horn sockets. AC Delco makes a version for less than $20]
 
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#4 ·
hey bro, i know this is kinda old, but i did the same thing recently. thank you by the way :)

and i noticed my switch and wires are running a little warm. not hot, just warm.
makes me feel that the switch is taking all the current, not turning on the relay.
did you have that issue ?
 
#7 ·
Fog light wiring question

So I came across your thread & did some investigating of my own on my TJ SE. It seems that it is only prewired from the inside for the fogs. I followed the two wires for the fog lights from the multifunction switch but once it hooks up to the harness that runs to the PDC the two wires don't exsist. I have an empty spot for my fog relay but no in pins to power the relay. So I went to a junk yard and picked up a PDC and removed the metal clips and have put them in the fog relay slots. Now my question is where does the green/white wire from the high beams come from? Does it come from the headlights or from the multifunction switch. Do I need to splice into it? I've got everything else in place it's just this one wire I'm unsure of.
Thanks in advance and sorry about the long explaination. :confused:
~Mel
 
#8 ·
Between the m-f switch & the headlights there is the big yellow (40 pin) connector in the left kick panel. Not far from there toward the firewall there is a splice point where that green/white wire takes off & goes to the cluster. Another wire from there goes to the relay on factory installed FLs. I don’t know if there is that wire on non FL models. If you don’t have that one you could splice into that gr/wt wire anywhere. Probably easiest to find at the headlight. The right one is not too far from the PDC so might be the place to try.
 
#12 ·
I have a '98 TJ Sport with no fogs. You guys are talking about a fog switch on the turn signal stalk? My owner's manual shows an optional fog switch where a blank knock-out is on the dash, next to the rear wiper and defogger switches.
My old Ford also was delete of optional fogs. In that car the harness and plugs were in the bumper, and there was a wire connector behind the blank in the dash for a switch. All I had to do was get the factory fogs, a switch and install a fuse.

I'm hoping it could be that easy with my Jeep. But I doubt it. I was thinking about just tapping into the headlights. They'll be on all the time(at night)anyway. Could the system handle an extra pair of 55watt halogens?
 
#13 ·
I have a '98 TJ Sport with no fogs. You guys are talking about a fog switch on the turn signal stalk? My owner's manual shows an optional fog switch where a blank knock-out is on the dash, next to the rear wiper and defogger switches.
My old Ford also was delete of optional fogs. In that car the harness and plugs were in the bumper, and there was a wire connector behind the blank in the dash for a switch. All I had to do was get the factory fogs, a switch and install a fuse.

I'm hoping it could be that easy with my Jeep. But I doubt it. I was thinking about just tapping into the headlights. They'll be on all the time(at night)anyway. Could the system handle an extra pair of 55watt halogens?
Yes the fog switch is on the turn signal stalk aka multifuntion switch or you can also put a rocker switch in the blank "knock out" in the dash. Your Sport might be prewired for fogs, I have an SE so it's only half prewired. I must've spliced into the wrong wire or something (which doesn't make sense because I followed the correct wires from the mfs to the connector that leads to the hood) cause now when I turn on my lights the horn honks and the interior lights blink. When I was poking around under the dash/steering wheel I noticed it was wired for an alarm system. I'm sure it's aftermarket because the PO connected a small black box with a red led light that also blinks when the headlights and interior lights go on.
:banghead:
 
#14 ·
The PO must have tapped into the "unused" fog light wiring when wiring his alarm. Now it sounds like you are tripping the alarm when you turn on the lights.

Aside from that, do the fog lights work? On with the switch, off whit the hi beams?

Was the alarm working before you started working on the FLs?
 
#16 ·
The PO must have tapped into the "unused" fog light wiring when wiring his alarm. Now it sounds like you are tripping the alarm when you turn on the lights.

Aside from that, do the fog lights work? On with the switch, off whit the hi beams?

Was the alarm working before you started working on the FLs?[/Q

The fog lights aren't working because I haven't spliced into the hi beams wiring yet, I'm afraid of what will start to happen if I do!! LOL!! As for the alarm, the keys didn't come with an alarm key fob. So it's basically just a useless box with wires under my dash. :nonono:
 
#20 ·
I was going to ask about this, but then found this. I have an 02 and I'm adding foglights. Everything seems to be the same as the OP described in his 06 except the color of the wires. On mine, there's a light blue wire coming from the relay in the PDC that goes to the lights, but I haven't been able to find the other end of it yet. I looked under the fenders near the parking lights and don't see any connector. Any suggestions would be appreciated. BTW, I got the multifunction switch with the foglight switch from Pepboys. Hoping to have a stock looking install.
 
#22 ·
Look at a wiring diagram?
Jeep Knowledge Base

And a note/caution I didn't see mentioned.
The factory harness is designed for 55 watt bulbs, 2 of them. Going to higher output bulbs or adding additional lights to the circuit, could get ugly.

I used the factory harness to act as a trigger for the relays for the four A/M lamps I added.
Can still get the same benefit of the high beam cut out, unless you want them over ridden and do the relay mod. Like I did.
 
#24 ·
I am doing a similar fog light project on my 2005 Wrangler X. It was built without the fog lights so I plan to put the older fog light switch in the panel next to the O/D switch. I have ordered the switch and hope that I can utilize the factory wiring but bypass having to install a new multifunction switch with the fog light control. I want to be able to utilize the fog light indicator light in the instrument cluster and the relays if possible. I will update this post once I get all of the parts and plans worked out.

Thanks for the great article.
 
#26 ·
Keep in mind if your new lights are more powerful, over 55 watts, you should not use the factory wiring to power the lights. Power them through relays and use the factory wiring to trigger the relay.
 
#27 ·
Bought my first Jeep this week ('06 Unlimited) and discovered that the fog lamps the PO put on a KC bumper mount are not hooked up. The MFS has the fog light function built in, the relay is installed in the appropriate spot under the hood, and I got 12V hot at the factory plug-ins under the fenders when I activated the MFS. Problem is that I'm not able to figure out what connector will "plug and play" with those connectors to actually hook up the lights, and I don't want to cut off the factory FL connectors. Had no luck at my local Auto Zone with generic headlight pigtails. Thanks in advance.
 
#30 ·
OP, what a fantastic post. Just finished doing this on my 2006 X. Added 2 KC Daylighters (100 W per). Followed your instructions and the lights came on first try.

To the poster who says that this method shouldn't be used for lights over the factory 55 watt specs: The harness that came with my 100 W lights uses the same gauge wire as the factory wiring except for the wire that would be wired to the positive battery terminal. If I used the factory wiring, this increased wire gauge on the KC harness seems to be mirrored in the factory wiring because the hot wires coming to the PDC from the battery are as large as the KC 100W harness.

Why do you think this is unsafe?
 
#32 ·
Then I looked into my fuse box and saw I was missing the Fog Light relay [35] but did have the fuse [19][Under Hood forward of Battery]



I spent some time and investigated these relay and fuse slots.



I traced two wires to the steering column, the white/yellow wire from the fog lamp relay [slot 35] and a red/green wire from the fog lamp fuse [slot 19] - After taking apart the plastic that surrounds the column I found these wires leading into a large plastic clip located behind the hazard light switch.



I removed the two wires related to fog lights and hooked them up to a rocker toggle switch. The Red/Green wire comes from the Fog Light Fuse mentioned above and brings power to the switch and the White/Yellow wire brings power from the switch to the Fog Light Relay [See relay image above - note where the white/yellow wire enters the relay housing.]

*Be careful at this point as there are a couple of wires entering this clip with very similar colors. Notice on my picture I am choosing the white/yellow paired with the red/green. These two wires are located next to each other and one space away from the white/green and green/white [hi beam] wires. There is another wire on the "top" of this clip that is cream/gold colored and looks very much like the white and yellow.



And heres my toggle mounted on the dash behind my light control stick. [Please ignore the dirt] Toggle has three wires - ground - power in [red/green] - power out [white/yellow]
What I meant to say & couldn't because the iPhone wrangler forum app kept crashing was that the "power" referred to as red/green is a pink with green stripe as can be seen in the center of the picture in focus. This is the under side of the power distribution center under the hood towards the passenger side. A fuse connects power (battery positive) from the other blade to the main positive connection of the PDC, like a bus bar on a breaker panel. In other words, all positive sides of the fuse slots are 1 piece of metal, connected.
 
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