Does anyone have a schematic showing where the diodes should be placed if one was to do the rear foglight mod, but keeping the rear fog function intact? I have a pretty good idea, but just want to verify the locations.

Thank you

 

Not sure what's involved with the "fog light mod", but if you're talking about using the foglight as a fourth brake light while still preserving its fog light function, the diode(s) will go in the new wire(s) running from the brake light circuit to the fog light, with the striped end of the diode (the cathode) closer to the fog light.

This will allow current to flow from the brake light wiring to the fog light, but will not allow current to flow from the fog light wiring to the brake light, so your brake lights won't come on when you turn on the rear fog lamp.

 

Yes, that is what I was talking about, and that is where I thought they'd be. (With correct "polarity" of course). I thought possibly there might be a need for some diodes in the factory wiring going to the fogs from the fog light switch, so as not to have power going to that circuit, but that switch shouldn't be closed at that time anyways, when the brakes would be being used.

And even if the rear fogs *were on* (by throwing the rear fog switch), it wouldn't matter, circuit wise, you'd just simply see the regular tail/brake lights go bright when the brakes were hit, because the fogs were lit like normal, correct?

 

As long as the rear fog light is just a single-filament bulb, then you're correct, applying the brakes would just supply +12V to the fog lamp wiring that's *already* at +12V because of the fog lamp switch being on - you wouldn't see any change in intensity in the fog lamp bulb.

But now that you mention it, a diode in the factory fog light wiring might not be a bad idea. Otherwise, applying the brakes might cause the indicator light in the fog lamp toggle to come on, even if you haven't turned the rear fog on via the toggle.