DISCLAIMER:This guide outlines the procedure I used to modify my 1999 QX4. I do not know what other years this modificaton would apply to. This mod may be illegal in some areas, please check local laws. Perform these modifications AT YOUR OWN RISK. I am not responsible if your lights go out in the middle of the night or if you and your Nissan/Infinity land a guest spot on COPS

PURPOSE:Performing this modification will change the behavior of the fog light switch. The factory design allows the fog lights to operate only when the low beams are on. The fog lights will now operate any time the ignition is on.

BACKGROUND:Prior to this modification, the headlights only worked when the low beams were on. Additionally, the fog lamps turned off when the high beams were activated. I drive with my headlights on during the days and wanted to be able to use my fog lights as daytime running lights. In order to do accomplish these goals, the lights would need to be wired in such a way that the fog lights would turn on any time the fog light switch was turned on regardless of the headlight status. In addition, the lights would need to turn off whenever the ignition was turned off.

OVERVIEW:The factory design uses a separate relay for the fog lights. The fog light relay coil circuit is in series with the headlamp circuit with the fog lamp switch being located after the relay. By simply replacing the relay's headlight power source with another ignition-based power source, we can achieve the desired behavior.

PROCEDURE:STEP 1-Located the relay box under the hood. Mine was on the driver's side fender. Identify the relay for the fog lamps using the guide on top. Mine was identified as "FR FOG". Remove the cover to expose the relays.

STEP 2-Remove the factory relay. I chose to preserve the factory relay and replace it with a relay from Radio Shack, part number #275-0226. You will need to trim the mounting tab from the relay in order for it to fit in the relay box. Locate the pin on the relay labeled "85" and remove it completely.



STEP 3-Remove the cover from the relay by prying it off with a small screwdriver.

STEP 4-Identify the post inside the relay that corresponds to pin 85. Solder a wire to the post. Be sure that you have a good connection. I used brown wire since this is a common color for a wire that is active only when the ignition is on. Drill a hole or cut a small groove in the relay cover and thread the wire through it.



STEP 5-Connect the brown wire to the new power supply source. I connected mine to the A/C relay in the relay box. I again replaced the relay with the same Radio Shack relay. Make the connection by soldering the wire to pin 30 and making a hole in the relay cover like you did in step 4. Do not remove any of the pins on the A/C relay. Replace the relays and test operation of the fog lamps and A/C.

If all goes well, you shall have independently functioning fog lights!

nice, looks like mine, good write up that big plastic tab on top of the relay can be cut off to look better

fueler wrote: that big plastic tab on top of the relay can be cut off to look better

If you don't cut it off, I think it will hit the cover on the relay box and crack it.

bmlawless wrote:You will need to trim the mounting tab from the relay in order for it to fit in the relay box.

there u go. see i dont even remember why i did that, i did the mod in 2004

Is this the same procedure that's needed for the S14's?

I would think so, the Fogs on my SE-R work the same as my Pathy, if you have a relay for the fog lights it will work the same.

MAXIMUS Nismo wrote:Is this the same procedure that's needed for the S14's?

Let us know - wish I knew about this when I had my S14a.

Im brand new to this forum and iv used this alot to find solutions to alot of different probs for my 00 QX4, but i was just wondering if the light mode shown above is the same for the 00' QX4? Also is there any suggestions on a suspension kit because i just bought 22's and i want my smooth ride back but dont want to sacrifice my wheels. any input will help, thx

well then you shouldn't have put 22s on it.

A very special thanks to bmlawless, I wired it exactly the same as you. Fog lights work independently from everything, work when high beams are on, and turn off by themselves when leaving the vehicle in the same nature as the headlights do.

Nice to know someone was helped from the write-up. The lights in your pic don't looks like the same yellow bulbs I have. Have you changed them out?

Question:I already have DRLs installed on the QX4. Is there a way I can wire the DRL's from the headlights to the foglights?

naladude.....

and lawless....those are stock bulbs, i was using my 6 year old digital cam, so the colours dont seem accurate

hey can i ask why you ran it from the fog relay to the a/c relay?can i run it to anything else?does it affect the ac in anyway?

Ran it to A/C because A/C gets power only when ignition is on, which is what you want with the fogs. wire it to say the supply power from the keyless entry and the lights will not turn off when you turn engine off and exit vehicle. You can wire it to anything that is on when ignition is on, they all share common power. It doesnt affect A/C at all, i drive with A/C and fogs on for a good hour on the highway and no issues

REZN wrote:hey can i ask why you ran it from the fog relay to the a/c relay?can i run it to anything else? does it affect the ac in anyway?

Qxxx4 is exactly right. The only reason I used the A/C relay is because power to that circuit is only on when the ignition is on and it keeps the wires contained within the circuit breaker box. It also does nothing to affect the A/C. If you were uncomfortable with doing it that way, you could probe around for any wire that is only on with the ignition since it is only pulling a small amount of current to actuate the relay.

that makes senseim hoping it works for pathfinders

Bankface wrote: i just bought 22's and i want my smooth ride back but dont want to sacrifice my wheels. any input will help, thx

Check this out: zer...e-22sTalk to JonathanPrem

REZN wrote:that makes senseim hoping it works for pathfinders

I used a pathfinder mod as my guide, so I can't see you having any trouble.

I did this along time ago.

you can also just mod the fogs so that they stay on when the highbeams are switched on.

I took the relay mod out because it kept killing my battery when i watch things on my screen for a long period of time. I hooked it up to A/C but i reguire the ignition to watch things and i always forget about the fogs especially during the day.

the highbeam fog mod is easy you just need to ground the ground wire from your fog light switch to a solid ground. This is because normally when you switch on the highbeams the ground to the fogs are killed thus shutting them off. Regrounding it will stop this ground killing issue very simple.

so you need to get two of the new relays from radio shack?

sandman614 wrote:so you need to get two of the new relays from radio shack?

You don't have to, but they are easier to open up and if anything happens all you have to do is pop the two Nissan relays back in.

nice thread im going to save it and do it soon, soo do you wire it to switch or ues exsiting fog light switch by headlight switch?

your still using the original relay location your just simply providing power to that relay all the time instead of only when headlights are on, so you still use your regular fog switch.

my relays look alot more different than these.i dont get it??

Nice write up. Shoot me an email for a custom title...

what gauge wire did you use?

sandman614 wrote:what gauge wire did you use?

The good news is that you are using all of the factory wiring for the lights and such so gauge isn't a huge deal. The only wire you are adding is the trigger for the relay which does not need to be very big at all. I chose the wire I used simply because it was brown which is sometimes used to indicate a wire that has power with the ignition. You could easily get away with 16ga wire in this application.

why are mines so wierd lookin? what do i do?