[actionseeker]

Ok, so to give proper context, I have to start with the fact that my set-up is a bit weird. The wiring is all OEM, however I have JDM fog light housings instead of USDM ones. I also had to swap the USDM connecters on to the JDM housings, but that required no wire cutting at all. Now, both use the same H3 bulb, so I figured they'd draw the same amount of power through the wires and I'd have no issues. Well, initially I had an issue where it ran fine for a bit, then started blowing fuses. I checked the wiring and it turns out that I had the polarity reversed on them, so I swap the pins on the connectors and they worked again. Well, fast forward nearly a year and the fuse is blowing yet again. I have to check the polarity and see if maybe I had it wrong this entire time, but an issue I had before, and will have again, is that the USDM (Red, Black) and JDM (Black, White) use different wire colors, and I'm not quite sure which is which. I can't find JDM electrical diagrams for the fog lights, so I'm a bit stumped. I ran off intuition last time and simply ran power directly to the bulb, and ground on the housing itself, but like I said, I need to check it again.

 

[TheKrimsonChin]

Great, I love it when I'm about to snag myself some JDM TRD Fogs and I see this post, I hope you figure out what's causing this.

 

[actionseeker]

Great, I love it when I'm about to snag myself some JDM TRD Fogs and I see this post, I hope you figure out what's causing this.

I will update when I have time to track down any faults. Don't let this scare you out of buying some JDMs, my case is unusual since I didn't exactly do things by the book.

 

[TheKrimsonChin]

I will update when I have time to track down any faults. Don't let this scare you out of buying some JDMs, my case is unusual since I didn't exactly do things by the book.

Is there a good tutorial on installing JDM Fogs the correct way on USDM Celicas?

 

[Bitter]

Does the fuse blow instantly or randomly?

 

[actionseeker]

Does the fuse blow instantly or randomly?

Instantly, it did that before when I had the wiring done wrong, but then I thought I had it fixed and it was fine for a year. Now, it's back to blowing them as soon as a flick the switch.

 

[Bitter]

Got a multi-meter with Ohms? Check the wire to the battery negative post to confirm it's shorted to ground. Probably rubbed through somewhere it's been routed past something else or gotten pinched.

 

[actionseeker]

Got a multi-meter with Ohms? Check the wire to the battery negative post to confirm it's shorted to ground. Probably rubbed through somewhere it's been routed past something else or gotten pinched.

I ended up taking everything apart and giving it all a good visual inspection first. I found two spots where I zip tied some wires a bit too tight, but otherwise everything is intact. I also removed my fog light housings entirely to verify that I did the polarity on the bulbs correctly. This is where the confusing part comes in. On the fog lights I have, there is a black wire and a white wire, which I wired up to be power and ground respectively. However, on the wiring harness the wires are white/black and blue/orange, and the original USDM fogs had one as red and the other black. I couldn't find the wiring diagram for this circuit so I merely tested which wire power went to (blue/orange, with black/white being ground), and wired it up that way.

It worked fine the first time until it started blowing fuses. I took it apart again, found out I had some wires mixed up, got them corrected, and it again worked fine again. This lasted for about a year, and it's now blowing fuses again. While looking at the housings, I noticed that the wires internal to them is routed oddly, and makes me think that perhaps it's shorting to ground inside because the power wire can very easily just touch part of the housing it's supposed to ground to.

EDIT: Yep, it was exactly what I thought. The power wire inside the housing is making contact with the grounding point, but I was able to remove a bit of slack from the inside of the housing to reduce chance of contact. I still don't like how close this all is, so is there any way I can insulate it?

 

[Bitter]

If you can slip heat shrink on it or wrap it in high heat silicone tape maybe? Gets hot in those tiny fog housings, tape probably won't stay taped.

Sent from my SM-G892U using Tapatalk

 

[eDonnelly]

EDIT: Yep, it was exactly what I thought. The power wire inside the housing is making contact with the grounding point, but I was able to remove a bit of slack from the inside of the housing to reduce chance of contact. I still don't like how close this all is, so is there any way I can insulate it?

There is this stuff called Liquid Electrical Tape that I really like for these types of jobs. They sell it at all big box home improvement stores. I recommend buying a cheap set of various size art brushes as well to apply it with precision b/c the can brush is huge.

 

[actionseeker]

I'll see what I can do, thanks guys!

 

[Bitter]

Leave the lid off the liquid tape for a while or leave it loose, it's far too thin to start off and it's hard to get a layer thick enough to insulate well without putting many many many coats on.

 

[eDonnelly]

Leave the lid off the liquid tape for a while or leave it loose, it's far too thin to start off and it's hard to get a layer thick enough to insulate well without putting many many many coats on.

It says on the can to mix it well and then apply as many thin layers as you want to build thickness. If you leave the lid open it will get crusty and then you'll have chunks in your can. Ask me how I know

 

[actionseeker]

I unfortunately don't have a better pic of the inside, but the bulb basically slides into a slot in the housing and as held down by those clips. You then route the wire around them and the bulb's wire goes to the power terminal, and the ground to ground. I'm pretty sure removing the excess slack in the wire effectively solved my problem, but the issue is that the power wire is literally just right there next to the internal body of the housing, which is where it's also supposed to ground. I tested it by touching and like I thought, it blew the fuse (and the bulb ugh). I had a lot of slack inside so that made it really easy for everything to make contact. Can anybody think of like, a thin sheet that can insulate and take heat and just be cut and then slipped into place?

 

[Bitter]

https://www.amazon.com/s?k=fiberglass+wire+sleeve&sprefix=fibreglass+wire+%2Caps%2C101&ref=nb_sb_ss_ts-doa-p_1_16

I think you'll find something that'll work there. The end of the spade the bulb connects to is supposed to be encased in plastic.

 

[2way]

Yeah, the female spade connectors should have a plastic covering.

 

[actionseeker]

Toyota Japan apparently thought they didn't, or they've been since lost to time. Do they sell the covers by themselves anywhere?

 

[Sheik Ya Bootie]

Electrical tape or a couple of pieces of shrink wrap.

Usually you’d crimp new fittings because you’re not going to get covers over it now .

 

[Bitter]

It probably crumbled off with heat and age, I bet someone ran high wattage bulbs and cooked it. You can slip heat shrink over it and shrink it down, some 3:1 ratio stuff ought to do it.

Sent from my SM-G892U using Tapatalk

 

[2way]

They sell new crimp connectors with the plastic or, as mentioned, heat shrink or tape over the joint. Pretty much anything to insulate it from contacting body ground.