DEGUZZI

Anyone use a JDM Silvia S13 fog light button for the factory fog light/DRL circuit in 240s?

The JDM button has 6 pins, but the factory fog light circuit only uses the lower 4


If anyone has a wiring diagram of the OEM fog light circuit and/or the Silvia fog light button, that'd be awesome, too



I found a couple semi-related threads, but they're missing pictures and super old

DEGUZZI

Well, I was bored so I went to answer my own question. I found some old threads with dead pictures, so I figured I'd start a new write-up with my own pictures to help out people in 2020+ lol


Thankfully the JDM Silvia fog light button is plug and play for the 240SX factory fog light circuit



On the button, the #1 and #3 pairs of pins are the switch

The middle pins (#2) are to power the button's light:





Under the dash, you'll find a black connector with a dust cover, tied up and tucked away:



Pull it through the cluster bezel and connect the button



Then you'll head to the relay box behind the driver side headlight, by the airbox:





You'll need to add a blue relay (PO# 25230-C9980) to the empty space [FR FOG]:



Cover it back up, and reinstall anything you removed to access it



Next we'll head to the part of the harness right next to the battery to find the fog light harness connector.

You'll definitely need to take the battery out to find it:





I found mine tucked under the harness by the corner plugged with a cover. It's a really short branch off the harness so you can't pull it out very far:





If you want to make your own sub harness, Wiring Specialties has a connector that matches:


>>S13 SR20 Knock Sensor Connector (Sensor side)

Pins on the harness-side connector:



When you have your sub-harness made accordingly, connect it to whatever you're trying to power and that should be that!



The only downside with using the factory circuit is that the low beams need to be ON for the button to turn anything on/off--no headlights, no fog lights

I was hoping I could turn them on with the at least the parking lights, and off when I'm not using any lights, but it's not wired that way unfortunately. If that's a circuit you can work with, there you have it

__________________
IG: de_guzzi

S13project

This is awesome! Thank you for this. Have actually been looking into this same thing after I found the fog connector under the dash and realized what it was and starting trying to figure out how much of the fog harness was actually in the car.

__________________

S14rebuild

Dam this is legit write up.