Restoring MPH/KPH switch on JDM/Aus vehicles (WIP)

[Luns]

Originally Posted by Futaba

With regards to the rear fog light, my Japanese GT86 also did not come with one (I believe it was not available at all in Japan on any model of the GT86 or BRZ.

I'd been watching on Croooober and have spotted the occasional reverse lamp with rear fog light (maybe one out of 30 lamps, none at the moment), so I'm pretty sure it was available in Japan if uncommon. Selling price was always quite reasonable, but shipping invariably costs more than the lamp itself. This would be okay if I could see things all the way through, but I see enough roadblocks I haven't bought one yet. I do have a UK stalk though.

Originally Posted by Futaba

But as a rear fog light was a legal requirement for the process of taking the vehicle with me and registering it for use on UK roads, I needed to have a working rear fog light.

What I found was that the loom in the boot that goes under the lower lip trim of the boot seal, has connection there, and the source side of the connector has an additional wire fitted to the connector that was unpinned on the connected section of loom.

So how I went about it was removing my center lower light cluster, drilling and notching the center cavity to match the left and right cavity openings, then sourced a bulb holder and wiring that matched the left and right, I ran the positive for this newly installed center bulb to the connector, adding the pin to the empty side of the connector, so that it uses the unassigned pin on the source side connector, then attached the other end of the bulbs wiring to ground, I then took apart my squib ring and swapped the right hand stalk (indicator/lights on the Japanese GT86) (with one from I think was an Australian vehicle in the end?) Which connected directly up to the stalks normal connector, which added a final switch state for that stalk (sprung so you twist against spring pressure and release to toggle it) and without any other modifications beyond the new stalk and adding the center light to the existing connector + ground, using the rear fog switch does as it is supposed to, and when your headlights are on, using it enables the rear fog light indicator on the dash, and turns on the center rear fog light.

I would imagine the same could be done with your vehicle without any additional steps, the key part is finding a indicator stalk for the correct side that has the rear fog light setting on it.

Aside from the stalk and fog light itself, you car was ready to go. Sadly, not so with US market cars. Literally none of the wiring involved is present. The spot in the fusebox that would be used for the rear fog in other markets, is used as one of the DRL fuses in the US. What's more, there are posts by 1GiantTurtle where he determines the US body-ECU doesn't respond to the input pin that controls the rear fogs. He ended up wiring his own latching relay circuit, bypassing the body ECU, and running a wire straight into the gauge cluster to light the indicator (which oddly enough _is_ populated despite not otherwise being used in this market).

I'm not holding my breath, but an hoping somebody with the appropriate skill set could determine certain bits of some eeprom to set to enable the BECU support. As long as the BECU output to drive the rear fog relay, and the indicator in the gauge cluster are both working, I could take things from there.