Is it possible to re-wire the fog/driving lights so that they will work without the head lights being on? For example, in my Mustang, I can run the driving lights with just the parking lights on.

'04 G35s 6MT Diamond Graphite/Graphite

 

I'm sure it's possible. It's just wires and switches. I don't know which wires it would be, but I imagine it would just be a matter of rewiring the fog lamp switch directly to the fog lamps instead of being dependent on the headlights being on.

This seems to be a new trend in cars, though, probably to keep people from running with parking lights/fog lights. You generally should run with the low-beam headlights on as well, if you need fog-lights (plus, it's technically illegal to run with just parking lights and no headlights (fogs don't count) in many, if not all, states).

My '01 Expedition will only run the fogs with the headlights ON. It won't even let you run fogs with the headlights coming on in AUTO. (You have to turn the headlights on, then pull the headlight switch out. Strange.) At least the Infiniti allows that.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

might not be so easy on this car. With the CAN system, the lights are pretty sophisticated, the signals go through a couple Intelligent Power Distribution Modules, and Body Control Module. Pretty advanced stuff if you look at the wiring diagrams.

2003 350Z & 2003 G35c
www.350zfrenzy.com
www.g35frenzy.com

 

Nah, it would be very easy...

It's as simple as this:

Find the wire going to the fog light switch that CONTROLS the fog light circuit relay. Now, remove it from the connector (or cut it if you choose) and splice another wire of your own to it. Then, simply attach the other end of your wire to the parking light circuit in your fuse box.

Now, you'll be able to turn on your foglights whenever your parking lights are on. They will continue to work totally independent of your headlights. And once you turn off your parking lights, the fog lights will also turn off, even if you leave the fog light switch "on".

 

Unfortunately, there is no 'wire going to the fog light switch that CONTROLS the fog light circuit relay'. As was stated before, the combination switch has five inputs and five outputs to control 25 functions (not all used). The BCM sends pulses to the five inputs and reads the five outputs to determine the state of all of the switches. The BCM sends signals over the Controller Area Network to the Intelligent Power Distribution Module which operates the Fog Lights.

Nothing is directly wired in this car! Even the dampers in the HVAC system are on their on little network. Just a bunch of computers 'talking' to each other over the CAN which makes it hard to modify anything without changing the logic in the control modules.

Gary...

 

The only way I can think of would be to install a relay, splice into the parking lights (to kick on relay when parking lights are on), run a hot from +battery to the relay, cut the wire that kicks on the each fog light (at the light housing), and run the hot from the relay to the fog light wire that was cut and goes to the light. I have not looked into this though. It might also be possible and easier to just replace the turn signal unit. I did pull this thing out (easy to remove) and it looks like it has points for this feature on the inside but is not wired for it. If you were able to order this part from over seas or somewhere were it's legal to run fogs with parking lights, you could just replace it. I read somewhere that the reason this feature is no longer available in USA is because it was illegal in like 4 states. Auto's used to be able to do this at one point I thought Although I had a probe, 95 Lightning, 2000 lightning and none of these were able to do this without splicing at the switch. Hope this helps

www.corevoltage.com

Stillen Box | Fallsgate Amp | Projection Fogs

 

NASA X-59 avionics tech here. Cars not my thing, but I‘ve changed out Honda CV axles correctly, so... I almost hit some dogs at 5am the other morning so I’m looking to improve my driving-in-the-middle-of-nowhere lighting, so I want my fog lights to work with the high beams on.

Aircraft have hundreds of relays...

From seeing the fog light schematic, it appears that the fog light relay is a four-contact relay in which two are the switch and two are the coil, for which the controller provides a ground.

With the car and lights OFF I am going to remove the relay, ignition ON, and test the four contacts with a meter for voltage. The two with 12 VDC should be from the battery bus, one for the switch, and one for the coil.

Then I’ll turn off the car and lights OFF again, reinstall the relay, turn on the car and fog light switch to ON, and probe the other two contacts. The one with 12 VDC should be the relay output going to the lights. I’ll set my meter to Ohms and test the last contact by putting one lead on the frame of the vehicle and the other on the contact. If I get anything other than OL (such as .#), the controller is providing the ground for the relay coil to close the contacts of the switch. If OL, the opposite is true. I can confirm this by turning on the high beams and re-Ohming in the same manner. The signal should now be opposite.

If the controller removes the ground to turn the lights on, I can cut off the ground contact of the relay. If the opposite is true, I can remove the relay permanently and install a short jumper wire from one of the 12 VDC battery bus contacts to the fog lights output contacts, but this would mean the fogs would always be on.

Installing a jumper from headlamp high relay output right above the fog relay to the fog relay output would make the fogs work with hi-beams but not with the vehicle exterior lighting off. If you have a 2011 or later model, you can install a jumper from the daytime running lights relay output right below the fog relay to the fog relay output, but this would mean your fog lights would be on whenever your daytime running lights are on.

It would seem the best thing to do would be to tap a single wire off the fog relay ground to one side an aftermarket switch installed under the steering column. The other side of the switch would go simply go to chassis ground. This would be your “FOG ORRIDE” switch to bypass the controller ground, which would still be available to you with the switch off.