Toyota wires are thinner

May 05, 2021 31 Replies

The wires in my Toyota are much thinner than the wires in any of my American cars were. I've had GM and Chryslers built from 1950 to 1995, and Toyotas from 2000 and 2005.



I'm not saying they are too thin, just thinner. Do you know why?



I see two poassible reasons.


1) Increased efforts to save money and help the environment, by using thinner and thus cheaper wire. Perhaps wires in American cars are thinnner now too??


2) Japan and the Japanese domestic auto industry after WWII was short of money and had to economize any way it could. Thinner, cheaper wires were one way, and now, even though they are making plenty money, they see no reason to change.


It matters only when I'm trying to splice wires, and I have to be more careful not to cut the wires while stripping the insulation. But the wires are so thin that there have been connections I don't try to make, because, where it's difficult to reach a wire, up under the dashboard, for example, that makes it even more likely I'll cut the wire and makes it harder to repair it.



I don't think it matters as long as the wiring lasts the life of the car. I've seen crappy wiring in Japanese consumer electronics, but again, as lon g as it lasts the product's lifetime and can carry the required current at the rated voltage, what does it matter?

I expect that the wires are thinner because they are carrying far less curr ent than they once did. Why? a) LED lamps instead of incandescent lamps. b) Digital gauges (if any at all) instead of analog gauges. c) Chip driven diagnostics.

I also expect that Toyota would not move to thinner-gauge wire purely as a matter of first-cost economics if one considers the cost of even a single r ecall vs. the heavier gauge wire. I also doubt if it is a 'green' decision any more so than any other realized efficiency due to refinements in techno logy and/or execution.

Peter Wieck Melrose Park, PA

3) Copper is expensive.

4) Weight. Every pound counts towards EPA fuel ratings. Seriously. IIRC, domestic cars use mostly 20Ga wire. I don't remember but Japanese may use 22Ga. There is a *lot* of wire in a car.

On Wed, 05 May 2021 13:10:37 -0400, micky posted for all of us to digest...

Did you ever consider that much of what a car operates on is computer controlled? The wire sizes are set for load by the SAE which any manufacturer would seemingly not violate.

If you have trouble cutting the wire while stripping insulation you are using a notch size too small, cheap stripper or a knife. The trick is to start with a bigger wire size and if that doesn't work go one size smaller. Let the stripper do the work. Wire gauge is opposite of size i.e. 22 gauge is smaller than 18 gauge.

If you have the green crusties then you have water ingress.

Put the wire back in the loom when done making sure it is as close to the location as it was. Some situations may require the loom/wire be relocated due to manufacturers defect /-(

Tekkie

The wires in your Toyota may not be thinner. Every manufacturer uses the sa me formulas and guidelines for determining wire gauge based on load. Some m anufacturers will have a minimum size they will use, based mostly on the ty pes of connectors that they want to use/have qualified for their vehicles.

Your Toyota wiring may have thinner insulation. Recent advances in insulati on materials have allowed for smaller diameter / thickness insulation that saves weight and bulk, and therefore fuel and possibly cost, although some of the newer insulation types are significantly more expensive than the ol der materials.

So in fact, it's possivble that your wire harness is of better quality and more expensive than some other makes....

There is so much cross pollination between manufacturers now that the diffe rences between foreign & domestic, or even just maker1 to maker2.... are es sentially meaningless.

So you're agreeing that the Japanese use thinnner wire than the Americans do?

Do you think it had to do with post-war poverty in Japan?

Have the Americans made their wires thinner than in the 1990's?

Are you capable of reading for content? The war (WWII) is 75+ years done.

Peter Wieck Melrose Park, PA

Nope, it took them quite a while before they did cars after the war and they included stuff that was optional on the local cars to get people to buy unknown cars.

Dunno. I've added another newsgroup, Jim in there prefers american cars, not sure if its recent ones tho.

The wires on 24V vehicles are thinner than them on 12V vehicles. Yes I do know why.

"Dad, why are the wires made of lots of little thin wires?" "There's one for each volt son." "Dad, I've counted the thin wires in this thick one and there's 84. So is that 84 volts?" "It's your bedtime."

Bill

I bought a trailer light harness for the Toyota. When I looked at the gauge of the taillight wiring and the tight location I decided I might do it some other day if I really wanted to hook up the trailer.

That model is rated for towing in the US so a Y connector wasn't available. Oddly in the Canadian manual it is rated for 500 lb max.

I think it's probably a modern vs older, rather than japanese vs american thing?

Car manufacturers seem to use "thin wall" cables now, using a tougher grade of PVC so that a greater %age of the overall volume of the wire is copper rather than plastic. Probably reduced copper too due to lower current requirements, as others have mentioned.

I thought it was to to with everything being CAN BUS now. Most of the wires just carry signals, essential power is carried by fewer thicker wires.

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Tim

Please don't feed the trolls

Very good.

My 50 Olds had room for a second battery, but it would have been a 2nd

6-volt battery. When you only have 6 volts, you often need a secodn battery, but I never got one. One December night it wouldn't start and for some reason I called AAA or something, and they couldn't start it either.

They sold a device that would rearrange the connections of the two batteries. Never had one but I think it went from parallel for charging to series for starting.

I'm guessing the tail light wires on the Toyota are 22 or 24 gauge. No problem for the application but considerably smaller than on my old ('86) pickup.

I have no complaints with the car but it is not over-engineered as was typical in Detroit's golden years.

Wrong, of course. You should have said "there is 10 for every amp" or similar.

Over-engineering is not good for the world as a whole. To do it "just right" saves on resources.

Also in a modern car thje tail lights will be LED and use less power, so the wires can be even thinner.

What I know is that my VW has LED lights at the rear and the wires going to these lights are thinner than what would have been used in the past for incandescent bulbs. The lights are controlled by a Can Bus signal. Car manufacturers have had problems buy computer type chips!

Michael Chare

Tail lights used to draw a couple of amps, requiring larger fuses, hence thicker wire.

You'll find that modern trailer harness assemblies, with built-in protection circuitry, sometimes have trouble with old incandescent bulb turn-on surge current in older trailers.

New cars may also have other kinds of limiters (faster), besides fuses.

How old is the VW and how do you find the reliability ?

I have always bought those new, a Beetle and a Golf in 73 but lots complained about small bits falling off in the 80s and 90s so I avoided them when I replaced the Golf in 2006 with a Hyundai Getz which never had a single warranty claim and no bits failing at all until just recently when there is some problem with the windscreen washer bottle which wont fill anymore which I havent got around to fixing.

I did have a few problems with the Golf, one head gasket problem under warranty, one alternator diode pack failure, the bonnet release cable broke, indicator relay failed, used quite a bit of oil and it wasn?t a leak.

The more recent than the beetles have always struck me as a bit more complicated than they really need to be.

But some nice stuff like the current Golf even helps you with the reversing camera when backing with a trailer. That would be quite handy, I cant even see the trailer when its empty with the Getz. Planning to replace the Getz with something since it has no cruise control at all.

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