Making fog light switch work even with headlights off?

[Jeff213]

I got some LED light bars for my truck and I want to be able to use them even if the headlights are off. I have them attached to the fog light wiring and I was wondering if any of you have made the fog lights work with the headlights off. Should just be as easy as bypassing a relay right?

 

[Celeborn]

Yes sir, I have done this on both of my 1997 Mercury Mountaineers. On my current one, I actually replaced the fog lights with two LED Light Bars, and they come on with the running lights, and will stay on even with the high beams on. And are still controllable via the factory fog light switch.

You have to run a wire from the running lamp on the passenger side, to the relay in the small relay box underneath of the air filter box.

I can't remember the color of the wiring off the top of my head, but if you can wait just a bit, I can get it for you. I believe there's a tutorial somewhere on the forum as well.

EDIT:

This is on a 1997

1) remove the cover and bottom from the relay block under the air filter box to expose the wires. (it is the small one toward the fenderwall)
2) which wires are what:
BK/Y = Constant 12v
T/O = 12v swithed(by relay) to fog lamps
DB/LG = 12v switch (when this comes on the relay switches on the lights)
LB/BK = Ground - goes to instrument panel switch, then to ground
3) cut the DB/LG wire
4) connect a new wire to it about 12" long
5) connect this wire to the brown wire coming off the parking lamp assembly (that's the + for the parking lamps)
6) test it!
7) close it all up and roll!

 

[meyek91974]

Does this make your fog lights independent controlled by the dash push button or that if the butting is pushed on then they'll come on with the amber lights?
Thank you for your help

 

[96Green]

Search for the "Fog Light Mod" that lets you turn the fogs on with the parkies, it's well detailed. The way the fogs work is that they are powered off the headlights (low beams), via a relay which is grounded through the dash switch. The relay, when grounded (by turning the switch on the dash to the 'on' position), allows power to flow from the low beam hot lead to the fogs. (when you turn the fog witch off, it interrupts the relay's path to ground, causing it to open and cut power to the fogs).

The 'Fog Light Mod' details moving the hot lead going 'into' that relay from the low beam to the parkies. If you move that instead to a constant lead off the battery (fused, of course), you can power the fogs on at any time, regardless of the headlight position.

The wire can be found under the relay box on the right side of the vehicle under the air intake. I do not recall the wire color.

In my case, I have my truck set up to allow the fogs to come on with the parkies (which has the side effect of also keeping them on w/ the low/high beam headlights).