Scion tC spec d Halo Light Installation Question

Hello! I have a fairly simple question that I can’t seem to find a direct answer to, so here I am.
I bought halo headlights for my car, they are (mostly) plug&play aside from the coolest part, the halo lights… I’ve watched numerous videos of different methods of installing them, some needing extra wire for splicing. Most or all videos never seem to explain what gauge wire is needed… I don’t know why this is so cryptic.
My question is, do I REALLY need extra wiring? I have these blue quick splice connectors, can’t I simply connect from the existing wire harness in my car, to the bare wire I have on my new headlights for the LED halo lights to work?

Here’s a link to one of the videos showing connections with extra wiring for both ground and positive.

Thank you to whoever can answer this! I’ll get to work on it today if my mind is thinking of this right and I don’t need extra wiring.
Image of wiring for LEDS:

I would never consider using those quick-splice blue connectors. If you want it to last, slice in the correct gauge wire, solder the splice, cover with shrink wrap.

Did these lights not come with installation instructions?


this is the only instruction for the LEDs.

The smaller wires a 24awg, those are the halos.
Theres another set of wires I’m assuming is 22-20awg that connect to another pair of lights.

Like I said this stuff is cryptic for no reason, even with all the DIY videos lol.

While I DETEST that you are installing these abominations on to your car… Why? See below.

I will tell you to look to the wire gauge ON the parts, and make use a larger size. Maybe just use 18 ga and be done with it. Smaller buys you NOthing but potential grief if it is too small for the current draw.

I also agree with @Purebred … do NOT use those blue clip connectors, they are wire cutters that will leave your car in the dark as they vibrate and chew through the wire. Utility trailers use those ALL the time… and how many of those have you seen at night with screwed up or NO lights? Lots!

OK, so why do I detest these add-ons…

How can you trust something as important as headlights to a company that can’t write a freaking installation instruction? Next, you are adding a significant light to the front that can create an annoying glare to oncoming drivers because of the same quality issues. They are technically illegal because they added rings don’t meet federal motor vehicle specifications for lighting especially if they have a blue glow… blue lights are for police only. And finally, the crappy electronics that drive the LEDs may interfere with your radio reception.


Booch.nail ( has to be a story behind that weird screen name ) you should read Mr. Mustang’s post twice . He is an automotive engineer who knows what he is talking about .

Also this Forum gets many posts from people who have made lighting changes to their vehicles and have had problems of all sorts.


First of all, thank you for the indepth reply.
Second, thank you for indirectly answering another question I was going to ask about using different gauge wiring, I only have 18 - 14awg and 24 gauge wasn’t at home depot or autozone.

As far as the choice of the LED lights, the OEM ones were clouded and probably more of a hazard to other drivers than the halos (plus they’re so cool c’mon) I wasn’t aware of glare or anything like that though.
It’s about to get dark here so I’ll have to go back in tomorrow anyways if I end up wiring the halos, I should have everything to do that already.

The “instructions” didn’t even list the gauge sizes for the loose wires, the wires themselves don’t have sizes either. So I was doing guess work with a wire stripper. I thought ikea furniture had vague manuals… :woozy_face:


+1–on all points–to the comments of both Mustangman and Volvo-V70.

I’ve lost count of the number of posts we’ve had over the past few years from people who tried to install aftermarket LEDs–in vehicles that were not designed for that type of lighting–and who had major issues. There were definitely a few who finally gave-up and reinstalled their old lighting units because the problems were so serious.

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The instructions are straight forward; black wire is ground, white wire connects to parking lights.

Select the location where you want to make the splice, do the supplied wires reach? If not, you need to add wire. 24-gauge wire is very thin, 16- or 18-gauge wire is better.

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If you don’t know how, aren’t equipped, or just don’t want to bother w/ soldering , suggest to use the standard crimp method. Inexpensive, easy for diy’er to do, and makes for a much more robust connection resistant to vibration than the other type. As long as there is room and wires are flexible enough, generally for a job like this there no issue w/using a thicker wire. Make sure to use stranded rather than solid wire.

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I had gotten a F-150 from a friend. his son got a new truck. his son put in headlights very similar to these that he paid a lot for. well, they worked, they did not work, or half the light would work. I got so frustrated with them that I ripped them out. I went to rockauto and bought new OEM headlights. problems gone. I wish you the best of luck with them.


You left out that they are, sometimes, just plain ugly. Have seen a few Jeeps with halos added, just not attractive at all.

One of the Saturday morning car shows hosts replaced the sealed beam lights on a 48 Olds with halos and LEDs, had to modify the headlight buckets to fit them. Result was ugly. Plus the Olds really needed $10,000 worth of higher priority repairs.

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Those are factory DRL.

Very true… but people do have different tastes… and some of these do look pretty cool. The OP does like them and that’s what counts when personalizing one’s car.

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Halo lights don’t seem like an appropriate styling feature for the G Wagon but people who sell $140,000 vehicles may know better than myself.

In green or orange, bad choice of colors in my opinion.

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It’s easy to tell when a Rivian truck is approaching you, due to the shape of the headlight halos.

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You can splice them into existing wiring but you need to be smart about it. Consider the existing wiring gauge and fusing is sized for the existing load(s) that they serve. There is always some margin but you are eroding that margin by increasing the load on the branch you are tying into. Do you have the current demand specifications for the halos? This would be first. Then identify which circuit you’d like to splice them into and it’s feeder wire gauge and fuse to see if it is compatible.

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Looks like the middle grill of an Edsel.

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