Wiring To Fogs and Switches...Unique Setup?

[TideTurner]

I have almost no automotive circuitry experience and am using this as an opportunity to learn so please bear with me...

I've been reading as much as I can and have a specific way I want my fog lights on the mod bumper to work in order to save switches but retain functionality. I want to have a white and yellow SAE fog light and a third more powerful off-road light. I would like to install the fog light switch (I have the harness in the bumper) and use that to power the SAE light but want to be able to toggle between the white and yellow depending on conditions. In situations where I want to use the third light I will be looking for as much light as possible so rather than dedicating an individual switch to it, I want one aux switch that turns all three in the bumper on.

So I think I can use just two AUX switches to do this (in addition to the fog switch) and I'll describe below. I TRIED to work out the wiring diagram as well but don't know what I don't know so looking for some advice on what I might have missed or am overlooking. So functionality wise I want:

- Fog Switch: Power fog light (either White or Yellow depending on Aux 1)
- Aux 1: When fog is powered, if this switch is open the White SAE would be on and the Yellow off. If closed, the Yellow SAE would be on and the White off.
- Aux 2: All 3 lights would be on regardless of Fog power.

Below is what I think the wiring would be but not sure if I need any additional fuses or where this setup might fail (or is overly complex). Any advise would be appreciated:

Also if anyone has suggestions on what I should look for in wire types or relays I really don't know where to start looking or what is quality and what poses risks...

Thanks

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[RagnarKon]

Okay I think I understand what you're trying to do but your diagram threw me for a loop... so I'm going to restate the desired end-goal and you can tell me if I'm crazy or not.

• You want the factory fog switch to turn on an off the fog lights as normal
• You want Aux 1 to be able to toggle between white and ambers, but this switch does not turn on/off the fog lights, it just sets the color.
• You want Aux 2 to override everything and just turn everything on, regardless of how the other Aux switch and factory switch is set.

Correct?

 

[TideTurner]

That is exactly correct. I very well know I may be overcomplicating things and could obviously just connect white sae to fog, yellow sae to aux 1, and the flood to aux 3 and switch each individually as I need them but thought this functionality would be fun to try to implement (and logical to use as each switch is more aligned with a “mode” or driving condition than a specific light).

 

[l88m22vette]

I would get the headlight switch with dual fog buttons to turn on the white fogs, use the lower button to switch to yellow, and then AUX 1 for all on. This puts the fog functionality in one logical place, and you save yourself an AUX switch.

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[TideTurner]

Not a bad idea but I’m not sure that would work. I believe the lower button controls a power source in the rear bumper so would have to tap that somewhere closer to the engine and seems like it might open a can of worms. Might be wrong though and would love to know if that’s an easy option and rear fog power source is identical to front.

Also, though, might want to use that harness / switch for rear lighting.

 

[Mdozier]

So now I'm confused. I thought if you got the modular bumper as original equipment you didn't have the integrated fog light switch with the headlight button.
I was trying to figure out how to conserve upfitter switches for a 3-light "fog" setup.

Will be watching here for education.

 

[Glade Runner]

I would get the headlight switch with dual fog buttons to turn on the white fogs, use the lower button to switch to yellow, and then AUX 1 for all on. This puts the fog functionality in one logical place, and you save yourself an AUX switch.

M2DZ-11654-CC

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This what I was considering doing.​

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Not a bad idea but I’m not sure that would work. I believe the lower button controls a power source in the rear bumper so would have to tap that somewhere closer to the engine and seems like it might open a can of worms. Might be wrong though and would love to know if that’s an easy option and rear fog power source is identical to front.

Also, though, might want to use that harness / switch for rear lighting.

Now I’m also curious if the dual switch will work.

In to learn!

 

[4x4TruckLEDs.com]

I have almost no automotive circuitry experience and am using this as an opportunity to learn so please bear with me...

I've been reading as much as I can and have a specific way I want my fog lights on the mod bumper to work in order to save switches but retain functionality. I want to have a white and yellow SAE fog light and a third more powerful off-road light. I would like to install the fog light switch (I have the harness in the bumper) and use that to power the SAE light but want to be able to toggle between the white and yellow depending on conditions. In situations where I want to use the third light I will be looking for as much light as possible so rather than dedicating an individual switch to it, I want one aux switch that turns all three in the bumper on.

So I think I can use just two AUX switches to do this (in addition to the fog switch) and I'll describe below. I TRIED to work out the wiring diagram as well but don't know what I don't know so looking for some advice on what I might have missed or am overlooking. So functionality wise I want:

- Fog Switch: Power fog light (either White or Yellow depending on Aux 1)
- Aux 1: When fog is powered, if this switch is open the White SAE would be on and the Yellow off. If closed, the Yellow SAE would be on and the White off.
- Aux 2: All 3 lights would be on regardless of Fog power.

Below is what I think the wiring would be but not sure if I need any additional fuses or where this setup might fail (or is overly complex). Any advise would be appreciated:

Also if anyone has suggestions on what I should look for in wire types or relays I really don't know where to start looking or what is quality and what poses risks...

Thanks

I mean if you are going to toggle the white/yellow from an upfitter you are not exactly saving a switch. If you plan to install a switch on the dash for this purpose, Yeah you could do it with a relay.

I'll be honest. I didn't study your diagram because I'd have to actually lay it out to verify what yuo have works (im not an electrical engineer, im not practical engineering where I just DO and adjust). But using a relay will solve that. Keep in mind you'd be powering a relay 24/7 in one position if it's not the standard position. That's not much of an amp draw but it WILL have a draw on the battery to keep a relay fired open for your toggle method.

You don't need 2 relays though since you're just changing the PATH of power essentially

 

[l88m22vette]

@fyd0 One way or the other you're wiring, so if you aren't going to use a rear fog/trail light it should just be finding one wire in the harness.

 

[RagnarKon]

Alright what you have will work... just need to fuse it. The fuse on the right is absolutely mandatory. The fuse on the Aux 2 line isn't strictly necessary, but I'd still do it.

Personally I'd do a SPST relay to control power to the Flood lights rather than powering it directly from Aux 2, but not necessary. It's just weird from a design standpoint to have a signal wire and a power wire coming from the same source.

You can also eliminate the two relays on the right and replace with a single DPDT relay if desired. But also not necessary.

 

[TideTurner]

So now I'm confused. I thought if you got the modular bumper as original equipment you didn't have the integrated fog light switch with the headlight button.
I was trying to figure out how to conserve upfitter switches for a 3-light "fog" setup.

Will be watching here for education.

Even though we don’t have the button(s) the harnesses are still there and if you order the fog switches you can power them (with some forscan changes). I’ll post some pics when I end up doing this but it will be a while and probably better threads out there describing that part.

 

[TideTurner]

Alright what you have will work... just need to fuse it. The fuse on the right is absolutely mandatory. The fuse on the Aux 2 line isn't strictly necessary, but I'd still do it.

Personally I'd do a SPST relay to control power to the Flood lights rather than powering it directly from Aux 2, but not necessary. It's just weird from a design standpoint to have a signal wire and a power wire coming from the same source.

You can also eliminate the two relays on the right and replace with a single DPDT relay if desired. But also not necessary.

Thanks so much @RagnarKon! Makes sense on the relay from Aux2 and depending on which switch I actually use I know they are different amperage so it also allows flexibility. Ill have to work through the DPDT on the right but think I know what you mean.

On the fuses, I’d definitely prefer to overprotect so will take the recommendations but is there a rule of thumb on where a fuse is needed and where one is not?

Thanks again for looking through this!

 

[RagnarKon]

On the fuses, I’d definitely prefer to overprotect so will take the recommendations but is there a rule of thumb on where a fuse is needed and where one is not?

Generally speaking... power circuits need fuses, data circuits do not. Any circuit that originates from a power source and is powering a load needs a fuse in-line.

So say, for example, something goes wrong with your right Amber fog light and it starts pulling WAY too much power. That'll trigger a gigantic current draw from circuit powering those Amber fog lights... which will quickly exceed the power capability of the relay, the relay burns up, then wires will start melting, and then fire starts, and then your Bronco burns to the ground. Bad. There is no fuse to protect that circuit.

If you have a fuse and your Amber fog lights start pulling WAY too much power, the fuse will pop and protect the rest of the circuit. No fire, no burned up Bronco. You'll have to replace one of your amber fog lights, but that's it.

The Auxiliary switch lines are already fused, which is why I mentioned earlier that the fuse on the Aux 2 line isn't necessary. But since you had this weird thing where the Aux 2 line is both acting as a signal and a power I... just... well... I added one for kicks and giggles I guess?? I don't have a good reason.

 

[TideTurner]

Generally speaking... power circuits need fuses, data circuits do not. Any circuit that originates from a power source and is powering a load needs a fuse in-line.

So say, for example, something goes wrong with your right Amber fog light and it starts pulling WAY too much power. That'll trigger a gigantic current draw from circuit powering those Amber fog lights... which will quickly exceed the power capability of the relay, the relay burns up, then wires will start melting, and then fire starts, and then your Bronco burns to the ground. Bad. There is no fuse to protect that circuit.

If you have a fuse and your Amber fog lights start pulling WAY too much power, the fuse will pop and protect the rest of the circuit. No fire, no burned up Bronco. You'll have to replace one of your amber fog lights, but that's it.

The Auxiliary switch lines are already fused, which is why I mentioned earlier that the fuse on the Aux 2 line isn't necessary. But since you had this weird thing where the Aux 2 line is both acting as a signal and a power I... just... well... I added one for kicks and giggles I guess?? I don't have a good reason.

Fantastic, that description helps a lot to help me visualize where they belong. Thanks again!

 

[TideTurner]

I mean if you are going to toggle the white/yellow from an upfitter you are not exactly saving a switch. If you plan to install a switch on the dash for this purpose, Yeah you could do it with a relay.

I'll be honest. I didn't study your diagram because I'd have to actually lay it out to verify what yuo have works (im not an electrical engineer, im not practical engineering where I just DO and adjust). But using a relay will solve that. Keep in mind you'd be powering a relay 24/7 in one position if it's not the standard position. That's not much of an amp draw but it WILL have a draw on the battery to keep a relay fired open for your toggle method.

You don't need 2 relays though since you're just changing the PATH of power essentially

Yeah I’m not saving switches really, just kind of like the idea of having fogs on and then the ability to switch from white/yellow as needed with one switch.

On the powering of the relay, I don’t quite understand why it will draw 24/7? The battery is a power source that potentially runs through the relay if the relay is closed (I’d get one normally open). Then the aux switch controls when that relay gets closed and those are only powered when the truck is on. I thought the only draw from the battery would be the light but curious if there is something I’m missing.

Separately, I’m looking at the diode dynamics lights you have as what I want to put in - SSC2 SAE Fog White & Yellow then SS3 White Driving. Will have to figure out how to tie into the harness a bit from the relays and fog power. I’ve seen a few off-road “relay sets” that are in a box and waterproof but don’t know if they are any good so any recommendations there would be helpful.

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