Driving / Fog Light Mod - Keeping Fog Lights on with High Beams?

[Blindaviator]

I have been looking into trying to mod the stock driving / fog lights to run with the high beams (I was able to do it to my old 99 Camaro pretty easily).

 

After researching around a bit I came to the conclusion that nobody has done much in this area other than adding relays to keep the driving lights on all the time which defeats the purpose of the switch on HL stalk.

 

I was able to find a good PDF on wiring for my 2001 Pathfinder. You can find the link below:

https://carmanuals2.com/get/nissan-pathfinder-2001-electrical-system-section-el-49179

 

After looking through the diagrams I think I figured out where the relay is that disables the driving lights on high beam.

 

Download the PDF and follow along:

 

It starts on page EL-87:

 

 

WITH AUTO LIGHT SYSTEM

Outline

Power is supplied at all times
I to headlamp RH relay terminals 1 and 3
I through 15A fuse (No. 59, located in the fuse and fusible link box), and
I to headlamp battery saver control unit terminal 7
I to smart entrance control unit terminal 10
I through 7.5A fuse [No. 24, located in the fuse block (J/B)], and
I to front fog lamp relay terminal 3
I through 15A fuse (No. 53, located in the fuse and fusible link box).

When ignition switch is in ON or START position, power is supplied
I to headlamp battery saver control unit terminal 1
I through 10A fuse [No. 16, located in the fuse block (J/B)], and
I to headlamp battery saver control unit terminal 10, and
I to smart entrance control unit terminal 33
I through 7.5A fuse [No. 11, located in the fuse block (J/B)].

Ground is supplied to headlamp battery saver control unit terminals 4 and 11.
When lighting system is in 2ND position, ground is supplied
I to headlamp RH relay terminal 2 from headlamp battery saver control unit terminals 2 and 8
I through headlamp battery saver control unit terminals 3 and 9,
I through lighting switch terminal 11, and
I through body grounds E13 and E41.
Headlamp RH relay is then energized.

Fog Lamp Operation

The fog lamp switch is built into the combination switch. The lighting switch must be in the 2ND position and
LOW (“B”) position for fog lamp operation.

With the fog lamp switch in the ON position, ground is supplied
I to fog lamp relay terminal 2
I through the fog lamp switch, lighting switch and body grounds E13 and E41.
The fog lamp relay is energized and power is supplied
I from fog lamp relay terminal 5
I to terminal 1 of each fog lamp.
Ground is supplied to terminal 2 of each fog lamp through body grounds E13 and E41.
With power and ground supplied, the fog lamps illuminate.

 

 

If you look at EL-90 diagram and at the "Combination Switch (Lighting Switch) E7 - E8" on left side near the center... The connector 10 at top to 8 on bottom is what interrupts the signal (it is obviously the high / low switch)... It seems to me you could add in a relay, activated with a switch, between the output of the "Combination Switch (Front Fog Lamp Switch)" 32 terminal to the output of terminal 8 of the Lighting Switch, jumping over the interrupt point (putting it straight to ground essentially), to supply power at all times on demand... Turning off the relay power would revert the OEM switch to regular operation...

 

But I am wondering if that could have adverse effects on the headlamps such as power back flow causing the high / low beams to stay on at all times?

I have read that Canada and Aussie versions of the pathfinders don't have this high beam interrupt switch... Possibly it goes straight to ground at all times?

Maybe cutting the wire between the fog and lighting switches and running the fog straight to ground would enable full use with switch?

 

Anyone have thoughts on this?

[Blindaviator]

Ok so after some trial and error I was able to modify the fog lights to run when high beams are on and still be able to turn them off with the switch.

 

This mod was done on a 2001. Don't know if wiring colors will be different for other years of R50's.

 

Now if I could figure out how to upload images here I could use one to show how easier.

 

After several hours of taking the dash apart, accidentally cutting the smallest wire you have ever seen in the hardest location to get to, I finally pulled my head outta my arse and did it the easy way.

 

If you have auto lights it uses the Hi/Low switch to interrupt the ground between the fog relay and ground. Just need to add a full time ground.

If you don't have auto lights it uses the Hi/Low switch to cut power to the fog light relay. Have to add keyed power source.

 

THIS WAY WILL ONLY WORK IF YOU HAVE AUTO LIGHTS !!!

 

1) Get down under the steering wheel and remove the 5 screws holding the top steering wheel cover on and remove the top part.

2) On the top left side you will see 2 white connectors. The small white one that only has 2 wires is what you need.

3) Unplug the small connector and peel back the electrical tape. One wire should be red and the other yellow with a black stripe.

4) Cut the yellow / black wire back from the connector far enough to strip and splice it.

5) Attach the cut end coming from the connector to a grounding source (the other end going into the wiring harness is not needed).

6) Check lights to make sure everything works.

7) Button it back up and you're done.

 

The fog lights should now stay on with high beams and the fog light switch should turn them off as well.

They still will not work unless the headlights are turned on since the fog relay gets it's power from the headlight relay.

 

 

THIS WAY WILL ONLY WORK IF YOU DON'T HAVE AUTO LIGHTS !!!

Since I have auto lights I can only go by the wiring diagrams for this modification

Same as above remove the top of the steering wheel cover and gain access to the switches.

 

According to the wiring diagrams the fog light switch still has 2 wires. One is black going to ground and the other is R/L (Red with lavender stripe?) that comes from the fuse.

The diagram shows that the R/B wire coming from the Hi/Low switch goes through the fuse and comes out R/L to the fog switch. You will need to cut one of the two wires and add power either just before the fog switch (R/L) or just after the Hi/Low switch(R/B). Make sure you connect the power wire to an accessory wire that turns off with the ignition key (it would be better to use a relay so you don't burn up the accessory wire or blow the fuse).

Either way you will need to fuse the power wire...

After adding the power your fog lights should work when hi beams are on and off with the switch. But unlike with auto lights it is likely the fog lights will work even when the headlight switch is off since the switch will always be powered when the key is on.

 

 

[NovaPath]

Thanks! Next night I have to tinker with the truck I will have to do this. It will be very helpful for night runs.

[01Pathmaker]

Awesome! I'll have to get this done asap. Quick question though, any idea on how to have the fog switch power on by the parking lights? There was a way to do it on my Titan utilizing a jumper wire but it rendered the switch useless. I'd really like to have the ability to run the fogs with any combination of lights on.

[Blindaviator]

Awesome! I'll have to get this done asap. Quick question though, any idea on how to have the fog switch power on by the parking lights? There was a way to do it on my Titan utilizing a jumper wire but it rendered the switch useless. I'd really like to have the ability to run the fogs with any combination of lights on.

 

If you don't have auto lights then you won't need anything more than the mod above.

 

If you have auto lights then the fog light relay is powered by the headlight relay.

When the headlights are turned on it also applies power to the fog light relay.

You would have to splice into the power wire for the fog light relay and add a switch / relay combo to energize it on demand.

[Blindaviator]

By looking at the wiring diagrams it looks like the R/B (Red / Black ?) wire on the fog light relay is the power wire from the headlight switch. You could energize that wire with a switched relay and get full time power for the fog lights and still have the operation of the fog light switch on the headlight stalk.

[01Pathmaker]

Hmmm, thanks for the research! Sounds like I just have to replace the power source into the fog relay by sending a new trigger from the parking light circuit. Now I just have to find the time to do it! Lol

[Blindaviator]

Hmmm, thanks for the research! Sounds like I just have to replace the power source into the fog relay by sending a new trigger from the parking light circuit. Now I just have to find the time to do it! Lol

 

Hehe yeah you could add a relay triggered by the parking lights to power the fog light relay. But if you wanted full time power to relay just trigger it with an accessory wire instead. Something that is powered on with the key.

[EricCR]

I've been trying to accomplish full independent fog light operation (with stalk switch fully functional, with parking lights and regardless of high beam state) through simply rewiring the existing relays (I don't want to fiddle with steering mounted stalks, switches or interior wiring).

 

There are differences between facelift model years in those electrical workshop manuals (check 2001 vs 2003 for example), so I'd recommend grabbing your multimeter, testing the relays and not fully trusting what you read.

 

Here's a Nissan lighting relay for reference:

 

The only thing you should focus on are terminals 1 and 2. Those have to be power/ground for the circuit to close and send power to the lights. It doesn't matter if terminal 1 is power or ground as long as the other terminal is the opposite. Terminal 3 will always be powered (regardless of key position) and terminal 5 sends the power out once the circuit is complete so you don't have to worry about those.

 

Now, you may think overriding the missing ground or power by bridging it from another relay (say, the parking lights one) is the right way to go, but I guess Nissan thought of this and made it a bit more complicated.

 

In my 2003 (with automatic lights), fog light relay terminals 1 and 2 behave in this manner:

• Once you turn on the low beams (light switch in position 2) power is provided to terminal 1.
• Once you turn on the fog light switch, ground is provided to terminal 2.

That turns the fog lights on.

Now, once you turn your high beams on:

• Ground on terminal 2 is interrupted and the fog lights turn off (power is still provided to terminal 1).

If you hardwire a ground to terminal 2, you will lose the ability to use the fog light switch and the fogs will turn on (and remain on) as soon as you turn on the low beams. What you can do is remove the ability of the high beam switch to interrupt the ground and that's what I think Blindaviator did by removing the steering wheel cover, but I am trying to avoid touching those wires, so we need to keep thinking.

 

So, let's tackle the easiest thing first: Getting the fog lights to turn on without the need for the low beams to be on (and retain fog light switch functionality). You simply hardwire constant power to terminal 1. That'll make them work even without the parking lights which may or may not be desirable. If you want them to be tied to the parking lights, it gets a bit more complicated. The parking light relay works the opposite way of the fog light relay. You would want to bridge fog light terminal 1 and whatever terminal from the parking lights is getting power, but the parking light relay instead gets ground (not power) when you flick the switch, so that's a no go. What about terminal 5 on the parking light relay which sends out power to the parking lights once the circuit closes? Wire that to terminal 1 on the fog light relay? Bingo!

 

Now you have fog lights that turn on/off at will as soon as you turn on the parking lights. They will still not work with the high beams, though. For that I haven't found any solution yet that doesn't involve the steps given by Blindaviator, but combining those two things would net you fully independent fog lights.

 

If you don't mind not being able to use the fog light switch, you can simply bridge fog light relay terminal 2 <-> parking light relay terminal 1. The fogs will turn on with the parking lights and will remain on constantly. Note: you'll of course need to remove whatever wire is on the receiving end to avoid a feedback loop, potentially blowing up fuses and other things.

 

EDIT: Here's the "pics or didn't happen" part:

 

Testing with a piece of wire (looks awful but of course I did it properly once I confirmed my theory):

 

Like nothing ever happened:

 

Parking + fogs:

 

 

Edited August 24, 2023 by EricCR

[Mrelcocko]

Nice write up friend.


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