Adding a rear fog lamp; adding a relay holder

Good afternoon, everyone.

I've added a rear-facing fog lamp to my 2024, and the project has stalled with the wiring.

I'm not unfamiliar with the circuit necessary, but I'm having trouble finding the right place to get switch power. Engineer-head: "I've got power (wires from the engine box to the light), but I'm struggling a bit with control wiring."

As I understand the local law, a rear-facing fog has to be tied to the taillight circuit. That is, the rear fog can't be on without the standard taillights being on. I understand that. Given that, I could tap the taillight fuse to power the switch, to power the relay, to power the lights. No sweat.

What I'd prefer to do, though, is to make it such that the rear fog comes on when the front fogs are turned on. I'm not sure how to go about that without cutting/tapping into a wire, and I'm just not going to do that. I've found the fuse for the front fogs, but it's energized all the time, so that's not as helpful as I had expected. I need to get into the circuit after the relay, or to tap the relay, and I just don't see a convenient way to do that.

Anyone done this?

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Second topic: the Caliraisedled relay holder.

I bought one. I like it. I know where I want to attach it, but I don't see two threaded holes readily available.

There's a pic on CR's web site of one installed -- but I can't tell enough from it. Maybe that pic isn't even of a T4R installation, I don't know. For now, it's attached to the inner fender panel, ahead of the hood strut mount (and rearward of the big fuse box), but with only one bolt. I can make that work, but it's unprofessional.

Who's installed one in their 5th gen, and where did you install it? Share a pic or two?

Thanks, all.


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ETA: I may have just found the answer to the second topic. CR's web site states, "2020+ 4Runner will need to relocate accessory fuse box." In that case, I've got some more work to do.

 

Hi. In your situation I would do one of the following (in order of preference.)

1. Ignore the legal aspects and put the rear fog light on its own switch. That way there is the possibility of using the light anytime at your convenience. Plus you can run power from wherever you want and leave the fuse panels alone.

2. I wouldn’t be afraid to cut/splice/tap into wiring. I’ve always felt that fuse taps were a dodgier solution than a Positap™ or crimp connectors. If your worry is causing confusion amongst the various modules and getting trouble lights on the display, plenty of folks get those using fuse taps. The modules don’t care how you’ve molested the wiring. The key is to tread lightly. I think if you just tap into the wires powering the fog lights and use them to power the signal side of a relay it will be fine.

 

Curious to see what your rear fog lights look like. Care to post some pics? Thanks!

 

You could use an H11 splitter at the fog light to get the signal (something like this:

$14 Headlight Splitter, H11/H8 2‑Way Splitter Wiring Harness Male to Female for Fog Lamp Headlight High Low Beam Dual Quad Projector

https://www.amazon.com/Headlight-Splitter-Wiring-Harness-Projector/dp/B0B6Z4Y7TY). It doesn't require tapping into factory wiring but it will be a long run of signal wire.

 

I'd really like to see this, your rear facing fog light. It sounds like a terrible idea to have it come on with other lights, and not independent. Is this like a "chase light"?

 

I live in Virginia also. I use one in the trailer hitch similar to this. It was wired as a tail / brake light. I spliced the brake leads on it to the tail leads so the brighter brake light is on when the tail lights are on. Plugged into the trailer light plug on the T4R. No need to touch any T4R wires.

$17 Nilight LED Brake Light Trailer Hitch Cover Square Red Lens Brake Light Vehicle Tow Hitch Driving Brake Lamp 12 LEDs Brake Tail Light with 2" Receiver for Towing Truck RV and SUV

https://www.amazon.com/Nilight-Trai...ts_id=15737381&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY

 

I like that idea. Thank you. I'd want to find the mating connector, so as to connect to the "split off" connector, to finish the setup. I'll surf on that momentarily. The review on that one in particular is not good, wow.

Not a chase light at all, really. Here's an article on rear fogs: https://specialtyperformanceparts.com/blogs/news/rear-fog-lights
Fairly common in Europe, not so much here in the States. I know Oldsmobile (RIP) put them on the Aurora a good long while ago, and you'll see them on some US-market VW/Audi/Volvo products. Here in the valley, we get some serious fog, well worthy of a rear-facing lamp.

Here's the setup, along with the work lights added early. (Mighty handy for loading or backing up to a trailer at night.)

 

This, honestly, may end up being the course of action.

I do understand what you're saying. I guess I'm just way reluctant to cut/tap into wiring on a vehicle this new. (I've never had one this new before!). With my older SUV, I wouldn't be so scared at all. Truly, I hadn't even thought about the modules getting all choked up about it. (Again, never had a vehicle this new before. )

Not a bad idea at all!

 

If you ARE legally allowed to have it in Virginia then it’s own switch is 100% no brainer

like @Acesandeights said…having those come on with reverse lights or taillights or etc would/could be “problemsome”
ie. Do you really want them on during the day, in front of a cop, where it’s already suitably bright…

I have a button for rear lights that yet to exist…possible “chase” more so rear lighting
Also the idea of extra back up came into mind but I know that requires an isolator/doohickie thing to prevent backpower

at your command is the plan

side note:
I get that you’d be adding peace of mind safety for other drivers behind you, but their lights will probably be on too…you’ll be towing the sun

 

Not exactly. Ideally, I want the rear fog to come on when I turn on the front fogs.

Driving a gray(ish) vehicle in some of the fog we get around here... I'm fine with the idea of towing the sun. (I like that phrase, btw.)
Years ago, I nearly crushed a gray Saturn in this thick fog. Dude was running his DRLs so I saw him coming up behind me, but after he passed me and slowed down he was darn near invisible [because he hadn't bothered to turn on any other lights].

 

I’ve got rear fogs wired up two different ways on ours. One has them on a separate switch that’s powered when the vehicle is on.



The other I tapped the driver’s side fog light and ran the wire back through the firewall, under the kick plates, through the interior cargo area panel, and down through the rear grommet. I haven’t installed an aux fuse panel in that one yet and am hoping to avoid it so this was the easiest way to install.



Both sets are also on DD C1R 7 pin dual output trailer wiring harness so they serve as reverse lights, running lights, and brake lights. When they are turned on via independent switch or fog light stalk, that overrides the brake light functionality.

 

Kezin, when I can get to a real keyboard (instead of just my phone) I'll have more questions for you.

 

I integrated mine into the tail lights. They took place over the factory reverse light location. I have the Diode Dynamics Tail as Turn harness which gives you 2 reverse lights. Instead of having 2 reverse lights I turned the factory reverse light location into rear fog lights.

 

Is that a Toyota switch?

 

No, it is aftermarket.

 

I lived in England for about 3 1/2 years in mid 90s. We had my GMC Jimmy and wife’s Honda Accord with us. Both had to have fog lights installed. When we returned, I left the fogs installed. When I traded the Jimmy for my first T4R in 2000 is when I figured out the trailer hitch fog mod. Have used it on all since.

 

How did you do that tap? Wire tap? I like PJSnow's splitter idea... I'm competent at at making wiring harnesses (it's an occasional part of my job), and would make my own if I knew more about the OE connectors. Are those Deutsch, or something else? Do we know?

 

So I have DD backlit SS3 Maxs out front. They came with the adapters to go from H11 (OEM) to DT. I pulled the main beam positive DT connector, cut it off, and crimped a new one on with a secondary positive wire for the rear fogs (also shortened the other wires to match). It’s run to the fuse box area with a single wire waterproof connector where it connects to the long run all the way back to the rear fogs. If you’re not going the DD SSC1R route, a splitter would be a good route. H11 to H11+DT and run it back. I would highly recommend the C1R though

As far as wire taps and fuse taps go, I refuse to use them. I think the fuse taps can be dangerous and wire taps can cause wiring issues down the road. I’d prefer crimped connections everywhere but will settle for soldered connections with long enough heat shrink to act as stress relief.

 

Thank you. I think I'm seeing how to pull this off now.
A little custom-harness work (build/buy/cobble together) and I'm off to the races.
I'm not familiar with the DT abbreviation though -- is that Deutsch, or another standard?

 

DT= Deutsch for someone who can’t spell well

 

Thank you! I think I'm on the path now....

The H11 mates to the existing (OE) fog lamp, right?

 

Should. The 2014-2020 used H11 halogens and the 2021-2024 have the same connector on the LED fog lights

 

We’ll find out on Saturday, assuming the parts I’ve ordered arrive on Friday as quoted…

 

Even when I had my rear cargo rack on, I still had the hitch fog light

 

I'd like to know more about that warning sign, Jimmy.

 

With my rear bumper I used an extra reverse light on the right and a rear fog on the left. My aftermarket front fogs are off a switch panel so I wired the rear fog to be controlled by the original front foglight switch.

 

I will neither confirm nor deny its intention LOL

 

That's fair.
Can you share a bigger pic? I can't read the small text.

(Oh, fudge! Maybe I'm getting old!)

 

can’t do, I sold that rack sign and all.

edit. I zoomed in and it says something like

All PC persons entering will encounter gravely offensive behavior and opinions

really fine print cites the ministry of PC act authorizing the behavior

 

After about a half-dozen false starts, I finally found a well-built adapter at the nearby NAPA store. Then I cut it in two, tapped the leads, and put it back together. I'm now using the existing fog light circuit to trigger a relay which allows current to flow to the rear lamp.

It's a crummy nighttime cell phone pic, but it shows just what scottiezilla said: it's like towing the sun!

I can detail the cable-and-relay setup later, if anyone's interested.

Thanks for the input, all.