Fog on w/ high beam using SP9100

Its insane how dark it gets out here in the SW away from the city lights. Makes for some mindblowing overhead views camping though.

 

So we can tap into the relay? I feel it would be easier to use the

$659 SP9100 Switch Pros SP-9100 8-Switch Panel Power System With Concealed Mounting Hardware

SP9100 .

 

my truck came with halogen headlights, but i upgraded to the OEM LED headlights. I wonder if I would still choose the halogen option....

 

Couldn't we just ground the wire under the grill where the fog lights plug into the harness?

I'm still not sure about all this.

I'm going to wait for the youtube how to video.

 

No, you couldn't.

 

So I plan to do this same thing but connect it to my Auxbeam switch panel-the reason isn't to have them on with high beams but to be able to put them on without turning my lights on (sometimes they are needed in bad MN weather but I don't want to dim my interior lights too).

I have Diode Dynamics fogs and I have ordered a new wire so my plan is to use that wire to connect my fogs to my switch panel instead of using the factory wiring at all. Still waiting on my wire, its being delayed by the back order of my ditch lights

 

You should have pigtails from the DD lamps to the Tacoma fog lamp connector. Or did you order generic ones?

 

Some states will not allow a vehicle to pass inspection that allow fogs and high beams simultaneously. Also bait for a pullover.

 

How many Tacomas are able to travel sideways????

So, you can see something beside you.....how do you manage to collided with it?

Fog lights are designed with a purpose. This is to throw a low, short, wide beam to penetrate UNDERNEATH weather. High beams will reflect off snow, rain and fog reducing visibility. Low beams are more effective than High to penetrate and fogs are specifically designed for this purpose.

Maybe my truck is defective, it only travels forward or backward, can't go sideways. Sure, it can turn, but its not a Willy Wonka Wonkavator.

 

I'm gonna ignore all these arguments why or why not you should have fog lights with high beams, everyone has their own reason. Whether it's wise or legal to do in your area is up to you. Pretty sure we're all adults here.

My 2017 truck has had fog lights with high beams for over 3 years now, without any problems. It's one of the first mods I did on my truck and it works beautifully.

But first, a little theory how the stock fog lights work. Caribe_makaira has touched on this earlier:
- Power for the fog lights flows like this: 12V comes from the battery and goes to the 15A FOG FR fuse. From there it goes to the FOG FR relay and splits path into two: one path will continue on to each fog light, and then to ground. This is the power side of the relay, the green wire on the wiring diagram. The other path goes from the relay to the B-ECU (Body ECU). This is the control side of the relay, the beige wire.
- Since there is no switch between the battery and the relay, it means the relay is always hot as long as a battery is connected. The way the B-ECU controls the relay is by controlling whether the relay is connected to a ground.
- If the B-ECU wants the fog lights off, it removes the ground and the relay unlatches, removing power from the fog lights.
- If the B-ECU wants the fog lights on, it connects the relay to ground, completing the circuit through the relay coil and the relay closes. The result is that the fog lights come on.

In simpler terms, this means: If the beige wire is connected to ground = fog lights on.
This will basically bypass whatever the B-ECU is doing and turn on the fog lights. It doesn't matter if the B-ECU want the lights on or off, the beige wire is already connected to ground so it will be on no matter what.

This leaves you with several options on how to connect the beige wire to ground:
- Wiring the beige wire directly to ground will result in the fog lights being on all the time, whether the truck is running or not. Basically the only way to turn them off is removing the battery. Not really all that good.
- Insert a switch on a "Tee" splice on the beige wire between the relay and the B-ECU, and then connecting the switch to ground. This will result in you being able to toggle the fog lights on or off manually with the switch. You can even toggle them on or off when the truck is shutoff. A little better, but it leaves the possibility of forgetting the switch and draining the battery.
- Install a relay to control when the beige wire is connected to ground. This is what I did.

I used the high beam circuit to control the new relay, which in turn controls the FOG FR relay. The coil, or "control" side of the new relay is connected to the left high beam circuit, and the other side of relay is connected to ground. That means whenever the high beams are turned on, the new relay will automatically latch. The "power" side of the relay is connected with a "Tee" splice to the beige wire, and the other side of the relay to ground.

End results are this: When the high beams are off, the fog lights function as they would stock, you can turn them on or off with the stalk as you like. As soon as you turn on high beams though, the fog lights are overridden and will be on as long as high beams are on. Since the high beams are off as soon as you turn the truck off, the overridden fog lights will turn off also and return to stock function. It works flawlessly with one exception: you won't have the fog lights indication on the dash come on since that is a function of the B-ECU which is commanding for lights off, but is overridden by the new relay. Although this exception is a non-issue for me.

My mod actually goes a bit further. The new relay I installed is a DPDT relay. One pole is used to override the fog lights and provide a ground. The other pole is used to supply power to my LED light bar (The Caliraised LED bar located behind the lower grill). So when I turn my high beams on, all my front lights come on automatically: low beams, high beams, fog lights, LED light bar. I live in a very dark area in central Alaska.

There is a slight power draw increase on the L/H high beam circuit that is used to energize the new relay coil. But the draw is so minimal (roughly 300 mA) it's negligible compared to the power draw of the high beams.

Pros:
- Seamless function of the fog lights with high beams. With this mod: high beams on = fog lights on.
- No switch is needed, no extra panel is needed.
- You can install an optional switch to control the new relay (this is what I did).

Cons:
- You will need to splice 2 wires, the beige fog light control wire and the L/H high beam power wire. Make sure you know what you're doing.
- Get comfy on how to read wiring diagrams.

I work with aircraft electrical wiring everyday on Boeing 777 and 767's, which means I'm very comfortable with modifying wiring. I know not everyone has that luxury, and splicing wires is not a fun job for many people. But I wanted to throw an option out there for you guys and to see how this mod can be done other ways. Maybe this will help someone out there.

 

Thank you for the detailed explanation! This helps for sure.
I’m still confused on relays and how to tap into them. Hence why I mentioned the

$659 SP9100 Switch Pros SP-9100 8-Switch Panel Power System With Concealed Mounting Hardware

SP9100 would be easier for me to use to get power to the fogs.
Could I tap directly into the power wire on the foglights? The SP is grounded so I’d assume this would work.
ive gained some clarity and some confusion. I’m alright at wiring but not sure about the relays.
I will keep asking until everything is clear to me. Thanks

 

I bought my DD fogs a year ago and have them plugged in just like the OEM fogs were but I have since ordered a new DD wire that will connect directly to my switch panel. So I won't be using the OEM fog wiring at all. They will be wired the same you wire a light bar or ditch lights

 

I am of your mind set. I'm sick of being blinded by the a-holes with insanely bright fog lights along with crazy bright headlights. HIDs or LEDs, I don't know which. Pisses me off!
I live in the boonies of NH and rarely have to use my high beams. Lots of deer here too! It's just an excuse.

 

You need this gif

 

I went ahead and ordered the britebox. Got a coupon so it was 10% off which was nice. It looks too easy to install and I think this will be exactly what I need. Without having to tap into anything else or use a switch on the switchpro.

 

Yeah, you're right. Nobody give a shit.

 

Let us know how it works I have been eyeballing that for a while but didn't want to be the guinea pig. Like you I don't really want to jump into tapping the harness and messing with factory wiring too much.

 

sounds good i will report back once installed.