IW STi Forum banner

How-To mod the 2004/2005 fog lights to turn on with 12 volts

Exterior 
21K views 41 replies 24 participants last post by  SpustaSTI 
#1 · (Edited)
How to mod the 2004/2005 fog lights to turn on with 12 volts.

I am not responsible for any damage that can occur with this mod.
Also know that it is illegal to drive with only your fog lights on in most states.

This mod is very simple to do and can be done to any Impreza that has the factory fog lights installed.

Tools needed:
- Long 16/18 gauge wire. (To tap into 12 volt turn on source)
- Heat Shrink Tubing. (To insulate the relay leg)
- Electrical Tape. (To hold everything in place)

What needs to be modded:
- Just the fog light relay next to the fuse box.

How to mod it:
- Unscrew the plastic panel under the dashboard. (Remove the plastic screw by the left door jam / dashboard area and unscrew the two screws on the bottom to take that piece off)
- Once the panel is removed you will see relays on the right of the fuse box.
- The third relay from the bottom is the fog light relay. (This is what you need to unplug and mod)
- Using two flathead screwdrivers on each side, unplug the relay.
- The Top Right leg of the relay is what senses 12 volts and switches the internal switch inside the relay.
- Bend the leg back so it folds over the side of the relay and points towards the opposite direction.
- Place some heat shrink tubing over the 16/18 gauge wire, then insert the wire into the hole in the relay leg and insulate it with the heat shrink.
- Wrap a little electrical tape around the relay to hold the wire in place and to make sure it doesn't get tugged or pulled off. Make sure you don't tape where the relay has notches to slide back in.
- Wire that wire to any 12 volt turn on source and the fogs will go on. I wired it up to the accessory on from the stereo harness.

I noted two things after this mod:
The switch fog lamp on indicator acts like it did before the mod. (It does not light up unless the headlights are on)
The fog lights turn off when the high beams go on. (I think this is to limit the amp draw possibly)

I have a picture that I drew on that should help.

Have fun with your new modded fog lights. :)
 
See less See more
1
#27 ·
I got the picture back up. The old host went down I guess.

The relay part number is the same one that comes with the fog light kit. I'll have to look it up.

It should work with the 07 Limited. I have had reports on NASIOC that it works. You can look at the thread there also.
 
#28 ·
I havent seen if anyone can confirm this works for 07 STI. Any help???
 
#30 ·
That link is not working on your page for some reason. Can I just follow the directions that are listed on this site for an 07 or is it different from the other subaru forum>
 
#32 ·
I just ordered JDM fogs... this sounds interesting... The thing that I like is that I can have my park lights and fog lights on and not use the headlgihts...

BUT, I DO want the fogs to shut off if I use the high beams... so this mod still enables the fogs to shut off correct?

Thanks,
-Nigel
 
#34 ·
Ok I want to do this now that my jdm fogs are installed.

But I have a question when you bend the leg on the relay how does it plug back in, ...it's a tight fit putting the relay in and now bending the let outwards how does it plug backinto the socket since there is more mass from the outside of the actual relay...

-Nigel
 
#39 ·
Just completed this mod on MY07 via using a piggyback fuse connector to the cig-lighter, that way the fogs come on when car is on or started. However, a few things..
1) The fogs stay on with the high beams
2) The fog switch doesn't light unless the headlights are on
3) The fog switch dims with the highbeams
4) The fuse door doesn't shut all the way.
5) The fogs don't come on with the parking lights on top of the steering column.

I'm using a 10A fuse on the piggyback, and I made my connections different. Instead of bending the relay or cutting the relay slot, I just mounted the relay onto the steering brace and ran wires to the relay slot and to the fuse box. Next I'll do the auto HID disable mod.
Here's a shot..

 
#41 ·
I'm using a 10A fuse on the piggyback, and I made my connections different. Instead of bending the relay or cutting the relay slot, I just mounted the relay onto the steering brace and ran wires to the relay slot and to the fuse box. Next I'll do the auto HID disable mod.
This is kind of off topic, but what is the relay just above the fog light relay used for? My 02 doesn't have that option, what ever it is, so the relay slot is open. After testing the voltages, I found the top left pin to be 12V when ever the ignition is on. So I wired the top right pin of the fog light relay into the top left pin of the relay just above that.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top