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
)
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.
