Automatic Foglights

[Rocket Man]

I saw someone else opened up the relay and soldered the wire to the pin so I tried to remove the case but it was glued on so I just cut a hole on it with a razor knife and soldered to the post, then sealed it up with black RTV. That way it’s even more sanitary. However I found out I needed to solder to the opposite corner than the one I opened up due to accessibility of the area inside to solder to. (You can turn the relay 180* and it still works) After I cut the corner out of the case, I was able to remove it so I could reuse the case without cutting the other corner open and just turn it (the case) 180* and reinstall it. The wire still needs to attach to the bottom left pin as the relay sits in the fuse box.

 

[gooffeyguy]

I saw someone else opened up the relay and soldered the wire to the pin so I tried to remove the case but it was glued on so I just cut a hole on it with a razor knife and soldered to the post, then sealed it up with black RTV. That way it’s even more sanitary. However I found out I needed to solder to the opposite corner than the one I opened up due to accessibility of the area inside to solder to. (You can turn the relay 180* and it still works) After I cut the corner out of the case, I was able to remove it so I could reuse the case without cutting the other corner open and just turn it (the case) 180* and reinstall it. The wire still needs to attach to the bottom left pin as the relay sits in the fuse box.

View attachment 252544

So the angled top edge on the case doesn't interfere with anything inside when you flip the case around?

Sent from my SM-G930V using Tapatalk

 

[Rocket Man]

So the angled top edge on the case doesn't interfere with anything inside when you flip the case around?

Sent from my SM-G930V using Tapatalk

You mean that little 45* bevel? No. Here it is in place. My add-a-circuit had to turn the opposite way as yours due to the layout so the wire takes a longer route. I’m gonna look into doing something different but not sure what.

 

[08z71bgm]

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



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.



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



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.



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.

This did not work for me. This actually turned on my tail lights. Parking lamps.

 

[gooffeyguy]

This did not work for me. This actually turned on my tail lights. Parking lamps.

So by activating your fog light relay it turns the tail lights on?

Sent from my SM-G930V using Tapatalk

 

[gooffeyguy]

Some of the '07-14 fuse boxes may have the locations of fuses and relays layed out differently. Look on the diagram on the underside of the cover for your vehicle's fog light relay and parking light fuses, don't just go by the pics I posted of my vehicle's fuse box.

Sent from my SM-G930V using Tapatalk

 

[08z71bgm]

Some of the '07-14 fuse boxes may have the locations of fuses and relays layed out differently. Look on the diagram on the underside of the cover for your vehicle's fog light relay and parking light fuses, don't just go by the pics I posted of my vehicle's fuse box.

Sent from my SM-G930V using Tapatalk

The diagram shows 25 as the add a circuit and it’s trlr prk(15)

 

[08z71bgm]

Ok the group of 3 15a fuses in line are what you used. The first one. However my fuel pump relay is under it and I think the fog lamp relay is powering my trailer lights/tail lamp parks.

 

[gooffeyguy]

View attachment 252771

Ok the group of 3 15a fuses in line are what you used. The first one. However my fuel pump relay is under it and I think the fog lamp relay is powering my trailer lights/tail lamp parks.

I think you may have the wire going to the wrong pin on the relay

 

[08z71bgm]

Which pin is it going to? 87/85/86/30