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I'm looking for suggestions on where to grab some power for fog lights. They're currently tapped into the constant power going to the horn relay, but I'm not wild about the load on that wiring (or the inevitability of me draining the battery). I don't want to go direct from the battery, as I'm trying to keep my wiring mess to a minimum.
Why not use the stock fog light wiring? There's a 2-wire plug to the right of the hood latch, that goes to the stock fogs. If your car didn't have fogs it's still there. You can probably get the harness that plugs into that then goes to the stock fogs used pretty cheap.
I did it ages ago on my car (94 R2). There was a little additional work but not bad I remember.
If you still need switch 12v for anything look on the fuse panel under the dash. Two unused female spade sockets above...IIRC think only one (on the right?) is hot with ignition on. I can’t find my picture but this one shows it just to the left of “sunroof”...
I considered using the stock wiring (in fact, finding that led to me getting fog lights to begin with), but the stock wiring (at least in my car) didn't extent all the way back to the switch -- at least I couldn't find anything there. So, since I had to run a line anyway, I figured I'd wire it independently -- that way I could turn the fogs on without the head lights also being on.
As for the dash power, I was really hoping to find a source under the hood, as to avoid yet another wire running back into the cockpit (I had to clean out several from defunct gauges the prior owner installed). Thanks for that picture and the detailed explanation though -- that will come in handy soon enough!
Any other thoughts for other under hood power? Otherwise, I may just run it back to the under dash fuse block.
If your car didn't come with fogs from the factory the wire to them does come into the cabin. Again it was a long time ago but I remember it wasn't a big deal to find that wire in the cabin and tap into it. Wasn't a whole bunch that had to be run to make a functional foglight switch.
I also set it up like stock where the fogs would come on with the headlights when the switch was on. If you wanted them all the time you could tap into the side markers or something so they come on with the side markers.
You should run a relay, source it from the main harness after the 100A fuse, then run the trigger through the fog switch and to the 12V switched source Sgtblue mentioned. I do not recommend powering the fogs directly via the 12V switched source, only use that as a trigger.
Figured this would be a good place to ask, The two spade terminals at the top of the fuse block are constant and switched, correct? What fuses do they go through, and how much amperage can be safely drawn from either one? Also, if the fuel pump rewire has been done, and the fuse is now located under the hood, can the 20A fuel pump fuse in the fuse box be used as a switched (and fused) source?
Figured this would be a good place to ask, The two spade terminals at the top of the fuse block are constant and switched, correct? What fuses do they go through, and how much amperage can be safely drawn from either one? Also, if the fuel pump rewire has been done, and the fuse is now located under the hood, can the 20A fuel pump fuse in the fuse box be used as a switched (and fused) source?
From what I've read, Yes these 2 terminals are constant and switched.
And I'm also very interested to get the answer of your other questions
I came across the same requirement for my standard model 1993 FD RX-7 (It's JDM spec) and thought I'd share what I did if someone else comes across this.
Looking at the original wiring diagram, we can see that we get a constant 12V supply from the 15A fog light fuse in the cabin to the fog light relay.
The fog light relay also has one constant ground and one switching ground - when we switch the extra ground, the relay passes the 12V source to the fog lights:
https://ibb.co/zHwWzQP
The switching ground on the fog light relay is a white wire - I did not want to dig through all the wires in the cabin but came across a quick fix (making use of the main light relay).
The lights relay has 2 constant 12V pins, 1 constant ground pin and one switching ground pin. When you turn the light switch to the first fog light position, this switching ground pin on the lights relay grounds:
https://ibb.co/wsHHnL8 (*fuse not fuze XD)
For this reason, I simply bridged the light relay switching ground pin to the fog light relay switching ground pin. When I turn the light switch to the first fog light position, the switching ground from the light relay is also used for the fog light relay - which is exactly what we want if we want to use the standard switch.
https://ibb.co/SmWd1GL
If you do this, please solder the white & gray wires together properly and wrap them up with electrical tape - I was just testing my fix here when I took the pictures.
