Automatic Foglights

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This mod will automatically turn on the fog lights whenever your parking lights come on and will keep them on even when using high beams. Thanks to @1BAD15 for the tip on doing this!

I originally did the 4 hi/low mod with the diode jumper between the headlight and foglight relay, but realized that the Yukons use the low beams as Daytime Running Lights and that mod made the foglights turn on with the DRLs, so basically they were on all the time.

I used an Add-a-circuit fuse tap for this mod. You will need one for Mini-ATM fuses. I picked mine up at the local auto parts store chain for about $7

foglight_2.jpg

These usually come with about 5" of wire and a crimp connector to attach to other wire. I had used mine previously on an old dashcam install so I soldered and heat shrunk more wire to it. You will need a total length of about 7" of wire to wire it like I have it.

In the underhood fuse box, find the three 15a parking light fuses that are lined up in a row, positions #25, 26, and 27. Any of these three will work, but I chose #25 because it didn't have any fuses directly above it to get blocked by the Add-a-circuit.

-position 25 is for trailer parking lights
-position 26 is for drivers side parking lights
-position 27 is for passenger side parking lights

*Side note: I have my two trailer/brake controller wires connected to the studs in front of the fuse box, so I don't know if these were not hooked up if it would effect power going to position #25. If yours doesn't get power when parking lights are on, then use one of the other two positions.

foglight_1.jpg

Pull the 15a fuse, insert it into the lower slots of the add-a-circuit, then install a 3-5a fuse in the upper slots. I originally tried a 2a fuse, but that blew, and the 3a seems to work OK. (see first pic)

*When I tried the 2a fuse I also still had the diode in the circuit, so I don't know if that had any effect on the fuse blowing.

Install the add-a-circuit into the position you pulled the 15a fuse from

foglight_3.jpg

Run the end of the add-a-circuit wire to the lower left position on the foglight relay. I stripped about 1/2" of insulation off the wire, stuck it about halfway into the slot, then inserted the relay back in.

foglight_4.jpg

That's it. Now the foglights will come on whenever the parking lights are on and are totally independent of the headlights, hi and low beams, AND will NOT come on with the Yukon's Daytime Running Lights.
 
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gooffeyguy
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No more diode?

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No diode needed in this setup.

Factory setup would turn parking lights on anyway when you turned light dial to off then pressed the foglight button.

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gooffeyguy
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What is the pin number on the relay you ran to? Was it for the coil to fire the relay or the load side to bypass it?
I haven't a clue. It's the same one used in the other thread that goes from headlight relay to foglight relay.

If it's on the load side, it'd be easy enough to switch though.

I would think it's the coil side, because I'm sure the foglights would use more than a 3 amp load and blow the fuse.

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George B

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I haven't a clue. It's the same one used in the other thread that goes from headlight relay to foglight relay.

If it's on the load side, it'd be easy enough to switch though.

I would think it's the coil side, because I'm sure the foglights would use more than a 3 amp load and blow the fuse.

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Good point.
 

08grey

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Didn't work for me

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gooffeyguy
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Didn't work for me

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More details?

Is your fusebox different, fog relay different?

I know on an older thread where they did it the original way from headlight relay to foglight relay it was mentioned that some fuse boxes have the foglight relay wired differently and that you should check to see which pin is the coil side of the relay.

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