There had been a thread on FitFreak.net regarding getting the fog lamps to work independently. I had followed it since I'm a bit of a light freak, but had not posted in the thread since I didn't have fog lights on my LX trim Fit.
From the factory, the Fog lamps will only work when the low beams are on. If they're not on, the fogs can't be turned on. And if you switch to high beam, the fogs will cut out. This is the mandatory way for fog lights to operate in some States for some silly reason. So Honda made it work this way for all North American spec Fit. This is however silly in my opinion. If there is indeed heavy fog, you don't want to have to run low beams. You want your light source as low as possible so you don't get the light shining too high and end up hitting the fog and glaring back at the driver. You're not suppose to drive fast in heavy fog anyway, so fogs and parking/taillamps will do. And when high beams are on, it leaves a bit of unlit space directly in front of the car, and fog lights would help fill that void nicely. This is why European spec cars are wired so fogs can be turn on with just parking/tail lamps, and do not cut out with high beams.
Well, after I got my Helm Service Manual, I tried to help out my fellow Fit owners by looking through the diagrams and trying to figure out a way to make the fogs work independently of the low beams. And fellow member Leonine took my suggestion and tested it on his vehicle with success, finally ending the 9 page saga on this issue on FitFreak. Anyways, here are the instructions:
1. Ground the fog light relay
Grounding the fog relay is easy. Go to the fog relay (bottom-right relay in the underdash relay/fuse panel), and cut the red/white wire. Then take the wire coming from the relay side, and connect that to ground. Finally, tape off the other end of the wire you cut.
2. Powering the fog light switch
Remove the top steering column cover and disconnect the 16-pin harness from the headlight switch. Look for the red/yellow wire and cut it. Then, connect a long piece of wire to the end coming from the harness, and run that wire down to the underdash fusebox. Once there, connect the wire to a spare fuse slot that is ignition switched. Then plug your 16-pin harness back into the headlight switch. And your fog light circuit is now completely independent from the rest of the lighting circuit, and should operate whenever you have your ignition on.
2a. Alternate location for powering the fog light switch
The above method will let you turn on your fog lights ANYTIME the ignition is on without having any other lights being on. If you want your fog lights to operate more light Euro-spec cars, with the fog being able to turn on only if the parking lights/taillights are on at least, then instead of using the #24 slot for power, tap into the #22 fuse, which is the one that powers the dash lights, front parking lights, gauge lights, license plate lights, and taillights. (Note: This method makes the circuit identical to the online manual for E-spec Fit, but no one on FitFreak has confirmed its operation)
And here's the link to the post I made in the FitFreak thread on this topic. Scroll down a few posts from my instructions and you'll find Leonine's pictured instructions on how to complete part #2 of my instructions (just don't forget to do part #1 as well), as well as pictures of the results; One of which I borrowed and posted here on my blog. Thanks Leonine for being my tester!