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Discussion Starter #1 (Edited)
Help Please ! Wiring Diagram

2015 Corolla S (Plus?)

I was attempting to install a power wire for an amplifier and i accidental cut the insulation on a wire in the wiring harness that passes through the large boot on the passenger side. The wiring harness must have rubbed against a burr on the sheet metal of the car's firewall.

I had the dealer check everything and the only thing they found wrong was this wire, which they completely cut before deciding they did NOT want to fix it. They told me the only option was to replace the entire wiring harness or find somewhere else that could run a new set of wires alongside the existing ones (but that they would not do this second option themselves).

The wires are a twisted pair (black/white wires) that are part of this harness. It has affected the main computer (i have no power steering or traction control and the RPM gauge, daytime running lights, oil temperature gauge are all not working at all).

I cannot find a wiring diagram anywhere, does someone have a wiring diagram of this harness so i can tell where these wires go?

Or have any recommendations? The Toyota dealer said they had a car come in with a similar problem and they attempted to repair by soldering the wires, but the car ended up having problems with the computer all the time. The car only has 5,000 miles on it, i can't believe something so small is turning into such a big problem.
 

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2015 Corolla S (Plus?)

I was attempting to install a power wire for an amplifier and i nickel a wire in the wiring harness that passes through the large boot on the passenger side. The wiring harness must have rubbed against a burr on the sheet metal of the car and cut through the insulation of the wire.

I had the dealer check everything and the only thing they found wrong was this wire, which they completely cut before deciding they did NOT want to fix it. They told me the only option was to spend $4,500 and replace the entire wiring harness or find somewhere else that could run a new set of wires alongside the existing ones (but that they would not do this second option themselves).

The wires are a twisted pair (black/white wires) that are part of this harness. It has affected the main computer (i have no power steering or traction control and the RPM gauge, daytime running lights, oil temperature gauge are all not working at all).

I cannot find a wiring diagram anywhere, does someone have a wiring diagram of this harness so i can tell where these wires go?

Or have any recommendations? The Toyota dealer said they had a car come in with a similar problem and they attempted to repair by soldering the wires, but the car ended up having problems with the computer all the time. The car only has 5,000 miles on it, i can't believe something so small is turning into such a big problem.
Can you post some pictures?
I am sure than you can replace the with out replacing all harnes.

Can you just take a same gage wire to make a jonction between the wire tha i presume now is short!?!?

Sincerly yours
 

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why not simply splice the wire halves back together ?

!! disconnect your battery prior to splicing anything electrical !!

Solder in a short piece of wire to join the two halves together,
and seal the splice joints well using liquid electrical tape
or heatshrink those splices if you do clean work.

Hopefully the folk whom first looked at it didn't short things out
when they clipped the wire in two !? :dunno:
Tho' damage could have already occurred
when you nicked the wire initially.
Especially if power was run thru during or after the fact.

If the PC got shorted out...
you'll likely realize that after you've re-spliced the wires.
But ya gotta start there to find out if other damage has occurred.
 

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I tried to take pictures but it is very difficult to get a camera in this spot. I will add a photo and a photo of the wiring overview they provided with the problem area circled.
Like you said whe don see it on photo.
Wath do you mean by "nickel a wire"
If one or 2 wires of harness is damage just install same gages wires between each extremity of harm wire. If harness wires not all the same color that should be complicated.
 

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...regardless of the year

The harness wire's look to pass thru a grommet mounted on the firewall
creating a seal + reducing the chance of damaging the wiring harness.

I wouldn't be investing in a replacement harness
as I would first attempt to repair the break in the wire myself.

I have cut and spliced the primary wiring harness several times
on both my '10 Corolla and '00 Tacoma.
Have always had success in doing that.

Though maybe tight for work space room...
It's not really an difficult repair that I see.

Of course repairing the wire's break
may not be the only issue or fault.
But you may not know for sure... until you try.

If you must pay someone to do it for you...
good luck with finding someone whom will accept that liability.
Hence the reasoning why the repair estimates call for a harness replacement.

Current techs will only repair using factory components that fit as they were intended.
And will generally not do custom repairs.
Not lazy mind you... but is a liability concern.

If you're willing to make attempt yourself...
You may get lucky in that repair.

If not willing to make attempt... I have no helpful advice to offer.

But wish you good luck with it.
 

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Like you said whe don see it on photo.
Wath do you mean by "nickel a wire"
If one or 2 wires of harness is damage just install same gages wires between each extremity of harm wire. If harness wires not all the same color that should be complicated.
That happened to me on my old Camry. Just take your time and extend the wires to put them back together. I traded in my car after that. I recall the car won't start, turn signals didn't work and I'm not sure what else. It was two or three wires I cut by accident trying to run my power wire for my amp.
 

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Discussion Starter #9
So here's an update:

I took the windshield wipers off, that plastic cowl, wiper assembly and motor, and the long metal pan under the wipers. Then I was able to have enough room to reach my hand in there and carefully strip the insulation back on each end of the wire and just twisted them together temporarily. I wanted to make sure everything worked and there was no damage to the computers or anything like that.

Long story short, with the wires twisted together everything was back to working like normal. So probably this weekend i will go back in and make a proper soldered repair and put heat shrink over it. I will most likely have to add a short bit of wire in between because i don't think it's quite long enough as-is.



The thing i learned here is that Toyota doesn't de-burr the metal edges so always be extremely careful when you wiggle a wire harness around or set it on anything. Especially the hole in the firewall where the rubber boot goes, i ended up cutting my finger when i felt it to see if it could have cut the wire.
 
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