A few of us on the NICO M forum are trying to figure out how to get independent fog lights on the M and no one really wants to take a stab in the dark and try things because these vehicles are so complex with wiring and so on so forth.
What many of us are looking to do is re-wire the fog lights in such a way that:
They can be set to on all by their selves and not have to be on only when the headligts are on. Similar to DRL. Meaning they are on when the car is on, but see bullet point 3.
Will stay on with the high beams. Some of us are running HID’s and this would be useful for maintaining HID life because constant on and off switching will kill the ballast. (the fog lights turn off when you activate the high-beam)
Operation of the fog lights still controlled via the switch on the steering column so they can be turned off if need be. Kind of like pulling the ebrake in a car with DRL’s to turn the lights off if you’re parked or what not.
And a post on the thread at NICO from an ASE tech who hasn’t replied back in that thread since the following post:
[quote=“SteveTheTech”"]
I can draw you all a theoretical picture but without a M to try it on it will be mere speculation until someone gets in there and does it. But here is what we are working with.
Above is a wiring diagram from the FSM of what exactly is in the fog light circuit on your cars. The IPDM controls most of the high current function of things outside the cabin. The BCM controls lower current interior functions. Things like the illumination circuits and fog light signals require a serious amount of communication between systems. The switches are operated by varying resistance and as you can see everything works together so fooling this signal might actually be harder than I originally thought. The BOLD wires are CAN and cannot (under any circumstances) be touched altered or probed. They are physically thicker than others and are sheathed in gray, avoid them at all costs.
I wrote*(*rewrote and edited when I was a junior Nico staffer) an article about doing this on a Frontier and it was simple. Just about everything on the M runs through at least 2 computers, or over the LAN network. Any of you who do IT and networking can attest that if the packets are altered or incorrect there could be a weird ripple effect.
I personally think the M might need a complete overhaul when it comes to lights (even with HIDs, they fade and have a finite life span). At this point a relay might be the way to go. I’ll work on a few things and try to get back here by the weekend. (Unless my big box from V-leds comes in :ohno: )
The M is a nice car but electrically it is fairly involved. Instead of T’ing off an accent light to run direct power to a light with higher current needs, let’s work on a system that will use that signal to trigger a relay or set of relays to power auxiliary lighting. Tapping will work fine but as you can see in the pictures this is a very complex (aka expensive to fix) car it is not worth the risk imo.
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Can anyone here possibly shed some light on this?
Someone else posted this link, but it’s to a 99 QX4, so I dunno if it will work on the M. I could certainly attempt this as this way is pretty simple but again, this is an expensive car with a complex system powering everything.
No real way to do it without getting into CAN programming. PCM controls the IPDM, which is CAN, and controls the fog “relay”. You MAY be able to probe/tap the combo switch at the fog reference wire before the PCM(you’ll need a PCM pinout diagrams or chart), and run a secondary wire with a diode to a separate sub harness(relayed/fused) that operates the fogs independently. There is no telling what body/chassis codes that may/may not trip when you disconnect the fogs from the system. I don’t work on those cars at all. Only one way to find out. Pull the fog clips off the bulbs and run the car w/o the connected. If no codes, then tap reference wire and build a harness to power them.
If a code trip for no bulbs, you may be able get away with measuring the resistance of the standard bulb, and wiring 1/4 watt resistors into the clips as bulb simulators. I’m not sure how advanced that cars’ body control module really is.
Thanks for the help. Sounds a bit involved, and I don’t know if I’d be able to design the necessary relay harness to do the job. I don’t want to go learning on this car either because if I F something up…yeah…
Mind if I post your reply on the NICO forum to see if anyone can work off that?
The relay harness for the fogs isn’t anyhting difficult really. Neither is the wire tapping, you’ll just need an accurate diagram of the combination switch-to-PCM to tell you exactly what wire is what, or a factory PCM pinout chart that tell you exacty what PCM terminal is the fog signal wire IN from the combo switch
(that tells the PCM to activate the fog relay in the IPDM)
Thanks. I’ll post up over there and see what happens. I’m not too comfortable, but if someone over there was to do your suggestion and possibly make a howto, I’d feel much more comfortable lol.
Yeah those wiring diagrams don’t tell you squat really. you’ll need a pinout. Might require a trip to the dealer and a little kiss ass to get it if you don’t own the FSM
If that’s the case though(and it is a full 12v pulse) he could use a switching relay that doesn’t require continuous power to remain in a closed position. Ultima GTR uses one to switch between high and low beam headlamp relays and operates off a 12v momentary pushbutton.
