Wiring gurus, a little help please?

[LONGJP2]

That's how it currently is set up

Although not ideal, your original drawing should work the way you want.
I agree you are probably getting some feedback.
Try unhooking the fog light signal from the low beams.
Diodes could work. You might want one on each input to the switch.

 

[LONGJP2]

Pin #2. Incoming power. Pin 1&3 outgoing power to your devices.

He's purposely using it backwards for 2 inputs / 1 output.

 

[dbbd1]

You said that your fog lights are wired the same way. Are you using the same type/style switch for the light bar? Your original post should work as shown. I am thinking that it may be the LED lighting in the switch. Try just a plain, non-lighted SPDT switch

 

[machoheadgames]

The only illumination for the high beam side of the SPDT switch would be a dependent illumination right? Meaning it depends on the switch being on to light up, and isn’t wired to something like the parking circuit.

Reason I ask is because that’s how it should be, but if you somehow got a way to wire the illumination to the parking lamps, you might have some feed in the switch backfeeding the high beam circuit, which is then barely illuminating the headlights on high beam mode through the MFS.

You for sure have the relay wired correctly for what you’re trying to do, I can confirm that much. I assuming something with your switch is the problem but I need to know more about what all is actually hooked to the switch. Ground for the illumination? Illumination power comes from where? Etc.

 

[B1Toad]

There is nothing wrong with the way he is using the switch, it's like a 3 way switch and the common can either be used for one supply and two loads or one load and two supplies, either way will work.
I think there is a chance it will work without the lights coming on dim if you use the wire that goes to the high beam dash indicator instead of the feed to the high beam under the hood, but first we need to make sure your high beam indicator operates from a 12 volt signal and that it is positive not negative. The 2004 is totally different than my 2000 and I haven't looked over the 2004 wiring diagrams.
The diode idea could work as well and you might try that before trying to figure out the high beam wire. (mine was easy, right there at the main wiring harness connectors by the left speaker)

I am assuming though that you tried it with the switch illumination disconnected to rule out a backfeed/bleed thru in the illumination circuit? (If the illumination uses the same circuit as the loads just unplug the ground from the switch)

 

[C.J. Roberts]

That's how it currently is set up

Look again. There are two wires coming from the battery. A red one to the relay, a blue one to the switch.

 

[B1Toad]

I looked at the wiring diagram and it shows the hi beam indicator wire as red w/gray 16 gauge from the indicator to connector C170 and from the other side of the C170 connector to the fog lamp relay it is red w/orange 14 gauge. C170 is the natural colored connector up under the dash next to the left speaker where the stack of large connectors is located.
I spent a lot of time studying the fog lamp relays when I was doing mine and I recall there was one relay that disabled the ground to the fog lamp relay when the high beam indicator is on. Not sure how much of the OEM stuff you used or if you just bypassed it all like I did.

 

[B1Toad]

Look again. There are two wires coming from the battery. A red one to the relay, a blue one to the switch.

Comparing your drawing and his, the same thing has been accomplished electrically.

 

[C.J. Roberts]

Comparing your drawing and his, the same thing has been accomplished electrically.

True. However I have seen it make a difference using a seperate wire for the switch.

 

[C.J. Roberts]

I looked at the wiring diagram and it shows the hi beam indicator wire as red w/gray 16 gauge from the indicator to connector C170. C170 is the natural colored connector up under the dash next to the left speaker where the stack of large connectors is located.

That's where I tapped into for my High beam power. The blue circle is the high beams, the yellow is for the backup lights.

 

[dbbd1]

OP- have you tried a non-lighted switch (or just joining the wires together by hand, in each “switched” position) yet?

 

[Ocho]

go dpdt with a diode and forget about it

here's an easy out for the diode if you don't want to make your own:

https://www.amazon.com/gp/product/B0002UHVHI/?tag=wranglerorg-20

 

[7slotMT]

go dpdt with a diode and forget about it

here's an easy out for the diode if you don't want to make your own:

https://www.amazon.com/gp/product/B0002UHVHI/?tag=wranglerorg-20

After messing with it for a good long while it does seem like I am getting a backfeed from pin 86 on the relay to the high beam circuit. For some of the other commenters, my switch is ran on a separate power wire via an add-a-fuse in the fuse panel. I've tried 2 different relays with the same result as well as 2 different switches. The light bar works as it should given how I wired it, so happy there. But I will have to see what happens after a diode on the high beam tap.