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Improved Fog Light Mod

53K views 17 replies 9 participants last post by  grnTitan04 
#1 ·
Rather than re-create the entire fog light circuit, it is possible to just replace the factory relay with one of your own and use 100% factory wiring!

First, Read this thread for reference, there is a lot of good information in here and plenty of helpful pics: Original Fog Light Mod
(Great work DipStick)

Then take a look at the attached .pdf's. They are pages from the Service Manual that describe the fog light circuit and function.


Now for the cool part...
 

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#2 ·
Am I missing something or have you not posted the cool part yet? :huh:
 
#3 ·
It turns out that the posts on the factory relay are standard spade terminal sizes.
No soldering required, get out your trusty crimp tool and go to work (see pic). I ended up filing down the thinner terminal to make it fit.

Basically, we are going to get rid of the factory relay and put in a new one where we can control when the relay is triggered. If you look at the socket (other pic) that the factory relay is in, you will see a pair of thin terminals and a pair of thicker terminals going the other way (upper set in the photo).
The thin set is the relay coil and the thick set are the contacts.

For the contacts, you need both, so slide in both spade connectors as shown.

For the coil, first read the PDF above. The factory circuit diagram shows that one side of the coil is 'hot' all the time. That is the white wire in the photo. If you have a tester, you should see voltage on this terminal even if the keys are out.
 

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#4 ·
The only thing left is to provide a new switch for your setup.
Just like the original factory design, the other side of the coil on your new relay needs to be grounded to complete the circuit. You can test it now by touching the remaining wire (black) to the battery negative terminal.
Fog lights turn on Woo Hoo! :upsidedow

To finish up, run a new wire to your switch, and the other side of your switch to ground. I suggest the stalk mod described in the Original fog light mod post, but if you are lazy like me, you can add a new switch to one of the blanks in the lower dash (see pics).
 

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#5 ·
Sorry mglick, I had to go back and shrink all the photos, took some time.
 
#6 ·
sorry to bring this back... but this is the way i want to wire my fogs (i think i have to do it this way anyway since i have an '04 XE KC). that said, i stumbled across a thread around here somewhere that had a picture and part number for an OEM switch that fit perfectly in the spot where the toggle is in this picture. not sure what the switch was originally for, but i'd like to go that route. i can't seem to find the thread again though. can someone link to it if they can find it?

thanks!
 
#10 ·
Yes, Hi, Lo, whatever. You can even use them without the key (so don't forget and leave them on and drain your battery).

Not completely sure that I understand the reason for the second question. Let me try this: you don't have to get the stalk, per se. You just need a switch someplace to turn them on and off, like I did here. the Stalk mod would be the cleanest way to get a switch, but if you are like me, you don't want to change anything that is difficult to un-change if you want to trade 'er in someday...
 
#11 ·
I just got done doing this mod and it took me a little less than two hours. Thanks to all of you who came before me, there is some great info here. I made a few changes that I thought you'd like to hear about. I basically combined your method here with the stalk re-wire method for what I think is the ultimate scenario. Here is a quick step by step:
1) Pull fog light relay and insert flat connectors to the top positions of the socket on the IPDM E/R and wire to the contacts on the new relay.
2) using test light/meter identify a 12v ignition source within the IPDM E/R wiring and solder to it and then connect it to one side of the coil on the new relay.
3) run a wire from the light stalk to the IPDM E/R and connect it to the remaining position on the new relay.
4) using the wire you just ran, perform the light stock re-wire as described in This Thread.

I know this may seem over-simplified but it is really an easy mod. Feel free to respond or PM if you need any clarification. If you perform this mod in the way I have described you will be able to turn your fog lights on with the factory switch on the light stalk any time you want but only with the ignition turned on which eliminates the concern that you may forget that they are on and run down your battery. -enjoy

For my next trick I am going to rewire my reverse lights to come on with the over head cargo lights using the switch on the dash - for those pesky tailgaters...:gunz: I will post pics and diagrams when I get around to doing the mod.
 
#13 ·
Ok I am so lost! Ok in the pictures where did the yellow and white wire come from? And what did you do with them? If you could post more pictures of it finished that would be great. I have the toggle switch ready and installed I'm just stuck on the tellor and white wire incident. So basically if anyone could help me ASAP that would be great because I'm in the middle of doing it. Thank you
 
#14 · (Edited)
I don't have the truck today, so I can't get more pics right now, but I will try to answer anyway.

Assuming you mean the first pic, which is the relay and the spade terminals. The Yellow White and Blue wires in this pic (with the spade terminals) are part of the relay base assembly from the new relay. The relay came as a kind of kit with a relay module and a prewired base.

The Yellow and Blue are the relay contacts, basically they are the 'switch' that is going to close and turn on the lights. The white is half of the circuit for the relay coil (the coil is the switch that turns on the switch mentioned above, confusing, I know, but bear with me).
When the White wire is plugged into the existing truck terminal (as shown in the second pic) it will be 'hot' all the time. To turn on the relay coil (and consequently, the lights) you need to ground the OTHER side of the relay coil (not shown). This grounding is accomplished with the toggle switch you already installed.

Helpful?
More confused?

EDIT:
This is nearly identical to the relay socket I used, should help explain the wires:http://www.parts-express.com/pe/showdetl.cfm?Partnumber=330-075
 
#16 ·
Okay...so those PDF files...what the heck are they? I read through this and I am more confused then ever.
I dont want to have to solder anything or tear apart the inside of my cab, put a new switch in, etc...
I want to install after market fog lights...use my existing light switch to turn them on/off.
When my parking lights come on...fogs come on...
When I click to turn my headlights on..the fogs stay on...
High beams...fogs on...
Turn everything off, they go off...
End of story...

Will this thread accomplish my mission?
If not...where do I go.
 
#18 ·
In short, No.

^^^ He has the right idea (add a circuit to the PL fuse) ^^^

You will still needs a relay. Add a circuit turns on the relay, output of the relay is between the battery and the new lights. Don't forget a fuse. Search for aftermarket fogs maybe?
 
#17 ·
If you buy an add a circuit at a parts house (looks like a fuse with a wire attached and a opening for a second fuse) and plug it into your parking light fuse slot the lights will come on anytime the parking lights are on. But having high beams and fog lights on at the same time is illegal in my state and probably yours also, so you will need a switch to turn off the fog lights to keep from getting a ticket.
The PDF are from the tech manual. $20 at the Nissan site for a one day pass. But they confuse me sometimes.
 
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