Fog Light Rewiring

Last updated: February 11, 2000

Steve writes on how to rewire the fog lights so they are not tied into the main lights. --Steve

Date: Wed, 7 Apr 1999 08:57:56 -0500
From: "Stover, Steve" (

I got the fogs rewired. The Mazda mechanic pulled a female pin connector out of an old wiring harness for me the other week, one with some 16/14 gauge wire still on it. I pulled the original feed pin out of the fog light connector and wrapped it. Its one of the big wires. The back (wire end) of the connector hinges up, then you have to push/prod/pry/cuss with some skinny/pointy gizmo until the old pin comes out. Stuck the new pin in, ran the wire over to the fuse box, since I didn't want to pull out enough dash to get to a cigarette lighter splice. Was going to run it off the unused fuse space, but it is constantly hot. With my luck lately I'd kill the battery in the very near future. So I took the wire and jammed it in with the cigarette lighter fuse (someone had done this same thing for power amp turn-on before I bought the car). Just be sure to put the wire in the fused side of the block instead of the hot side or the lights will NOT be fuse protected. But now that I can actually use the fog lights for fog I'd like to upgrade the bulbs if possible...

The way I'd LIKE to do this is change the fuse block - move the cig lighter circuit to the always-powered unused location, and then correctly wire the fogs to the old cig lighter point. That way I could use fuses for all and not have any wires pushed in to the fuse block. Guess I'd have to check on what all was on the cig lighter circuit first, though. Also, I don't know how hard it would be to remove and rewire the fuse block...


See the fusebox relo page on this site or at Chuck's page --Steve


Date: Sun, 01 Jul 2001 19:08:03 -0400
From: Gil (
Subject: (rx7) [3] Stock Fog Lights

To those of you who have stock fog lights and would like them to run independent of the headlights, I found the solution. There is no FAQ or "How-to" on how to perform this modification anywhere that I could find on the Internet.

Originally, I wanted to run my fog lights independently of the headlights because I am running 90 watt low/130 watt high, bulbs in place of the stock bulbs. I didn't want to run all that current through the headlight switch. Others want to be able to turn on the fog lights independently.

Well, as I had been looking for a red wire with a yellow stripe (R/Y) underneath the dashboard, I got discouraged. I couldn't find the connector that was leading out of the headlight switch to the fog light switch. It hit me like a ton of bricks. Why should I look underneath the dashboard? I'll go straight to the source - the fog light switch. If someone wants to put this in a FAQ or how-to, please go ahead!

Here's what I did to make the fog lights work independently of the headlights:

  1. Disconnect the negative side of the battery.
  2. Lift up the center console that contains the shifter and ash tray. Take off some of the foam covering the wiring to be able to see the R/Y wire. Cut the red wire w/ yellow stripe (R/Y) next to the fog light switch, halfway between the white connector and the fog light switch. Place a butt connector on the end of the wire attached to the fog light switch. Take some 14 gauge wire, connect it to the butt connector and run it to a 30 amp relay (I picked mine up from Radio $hack). Note: I covered the part of the R/Y wire leading out from the connector with some electrical tape, as it won't be used.
  3. Run some 14 gauge wire from the battery through the firewall to the 30 amp relay. Near the battery, splice in a fusible link that has a 30 amp fuse. Inside the car, take a phillips head screwdriver (or something similar, long and slim) and make a hole next to the steering rack. Run the wire through the firewall. Notes: I ran the wire from inside the car to outside. It is much easier to run it like this and you don't have to reach down below the brake booster to find the hole. I went with a high amperage relay and fuse combination, as I may want to upgrade the 35 watt fog light bulbs to a higher wattage in the future.
  4. Add a ground for the relay.
  5. Splice into the wire that turns on the light bulb for the ashtray. This goes into the switched part of the relay. Notes: I did this for two reasons. Number 1, I like the way the car looks with the parking lights on and the fog lights on. Number 2, If I ever forget to turn the lights off, the "lights-on" warning beep will sound when I forget to shut them off.

Everything works great! But, for those of you who want to run with out a relay, go ahead. Perform steps 1, 2, and 3. Except you won't be running to the relay. you'll be running directly from the battery to the fog light switch. Make sure you put a fusible link near the battery. I ran 14 gauge wire. I believe 16 gauge is the smallest gauge you'll want to run.

I wonder why Mazda never put in a fog light relay in the car. There is an area for one, but when I popped the top of the relay box that contains other relays, no relay for the fog lights was there!

For anyone attempting this mod, I take no responsibility for your actions. Use it at your own risk. If you have any questions on the mod, feel free to e-mail me.


Also see the page on how to rewire the fog lights to act as Daytime Running Lights (DRLs). --Steve

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