Fuse Box Corrosion and Fire

[Seanz0rz]

I discovered yesterday that the line to the fuse box under the hood corroded and caught fire:

with a flash to see the extent of damage:
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/IMG_3104.jpg


without a flash to see the green color of the wire:
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/IMG_3106.jpg

so what do you think happened? the only thing i can think of is at the end of September i drove through some salt water on my way off the beach at pismo. currently, the battery is disconnected, and it will remain like that except for moving the truck. i have no idea how long it has been like this, as i haven't opened that fuse block since last year.

thanks for any help you can offer. looks like it is time to replace/upgrade that wire!

[corax]

Corrosion build up increased resistance which generated heat and melted everything. I've seen this on alternator leads before. My guess is it's been corroding for awhile, not just since September. At least it probably didn't actually catch fire or it would have likely spread . . . still not good though

Now you have a good excuse to "up" the lead 1 gauge size and reduce the voltage drop to the rest of your system :D

[Seanz0rz]

yeah i instantly knew what had happened with the corrosion, i just cant figure out what would have corroded it so fast, the only thing i can think of is the salt water. im suspecting i might find problems elsewhere. i have replaced the wire to the starter, and the ground. the wire between the alt and the battery and the fuse box were left for another day, today looks like that day.

that wire appears to be either 6 or 8, so i will upgrade to 4 (which it definitely is not currently)

i actually have some left over from the vw rewire, but wont get a chance to work on it until friday or saturday, seeing as im spending roughly 55 hours a week at school or driving to/from.

[Bob98SR5]

Sean,

How much of the 4ga wire do you have? I have been wanting to upgrade the big 3 wires for some time. it would be great if you can document the length of the wire you will replace and the other two should you get to them.

[Seanz0rz]

IIRC i have 6 feet, which should be enough to replace what i need to replace. i already did the battery to starter, which i think was also 6 feet.

[slosurfer]

I really don't see how it would have been salt water getting up there, but who knows. It will be interesting to see what the whole wire looks like when you pull it.

Maybe there's a rip in the wire caseing down lower and it corroded all the way up the wire inside the caseing.

[Scuba]

Is that line easily reachable when you open the fuse box lid? I think that line is the problem to my electrical issue. But, I didn't know how to get to it.. so I haven't been able to check it.
When you pull it, would you mind measuring the length of the wire for me? I'd like to extend mine an inch or two..
Thanks Sean.

[4x4mike]

I blew the ABS fuse once and had to take the entire fuse box apart to replace it. Let me tell you it was a PITA but I'm glad I did it because the bottom of the box was full of moist sand. Sean I'm thinking that if you got water in there it stayed in there for a while and messed things up. I forget how long mine had been full of sand but I didn't have any corrosion. Might be worth it to take the box half way apart and peak inside.

[YotaFun]

The only time I have seen corrosion like that is here in the northeast.
Like Keith said Sean, that corrosion looks like it was a long time coming.

I need to do that big three mod myself, probably will when I tackle the 99+ interior upgrade.

Mike its interesting you say you had wet sand stuck in the bottom of your fuse block.
Makes me want to go check mine due to the number of times I have been through water and deep mud here...

[corax]

If you think there might be corrosion or salt in the fuse box, pull it out and rinse with rubbing alcohol to flush anything out. Make sure you let it drip dry and run a bit of air from a hair drier through it to thoroughly dry the insides. If there are any electronic bits in your fuse box alcohol won't hurt anything.

[4x4mike]

There are openings on the bottom of the box but they didn't seem to be working. I'm sure the sand was there for a while hiding out. It would hold onto the moisture and I'm glad I caught it before it caused damage.

[Seanz0rz]

wow! looks like its time for me to pull it all apart then. the plastic is melted pretty bad, i wont know how bad until i remove everything. i might end up looking for a parted out/junk vehicle to pull a new one from and replace mine.

exactly 1 year ago i installed the winch, and i KNOW the wire was good and clean then, so this is definitely within the last year. the past few months ive been smelling a burning, but chocked it up to oil i have spilled and other things. specifically Dec. 15th. it was raining that day, but not much.

[4x4mike]

What's the other end of the wire look like? It's mounting location?

I hated pulling the box apart. It was just a PITA. You might be money ahead to buy a new box and swap over what you need.

[Seanz0rz]

all of my "car cash" is sufficiently tied up in the vw at the moment. we have a bit in savings, but the idea for that is to buy a car that, you know, works... haha. pick n pull and others charge 40+ dollars for a fuse box of that size (i should know, ive purchased more than a few for the vw project)

i am not sure where that wire goes. i believe it goes directly to the battery. ill have a looksee when i go out to hook it back up to move it away from the driveway entrance.

[YotaFun]

Sean your right that goes straight from the battery

[corax]

wow! looks like its time for me to pull it all apart then. the plastic is melted pretty bad, i wont know how bad until i remove everything. i might end up looking for a parted out/junk vehicle to pull a new one from and replace mine.



be careful you don't twist the bolt/stud out of the fusebox when you go to take that nut off. most of the time, the bolt/stud just has a square head that fits in the plastic (now melted and deformed). If you think you might reuse the fusebox, put a vise grip on the bit at the end without threads and use a closed end wrench to break the nut free

[Seanz0rz]

Sean your right that goes straight from the battery


i am not so sure about that. i believe it might come from the alternator.

i have not cut the loom open yet, but there is a wire that goes straight from the battery to the fuse box (enters on the lower left of the front facing side). i believe this wire might go to the alternator. i only got a brief look at it this morning, i will investigate further this weekend.

i find this problem truly strange. i have had zero electrical issues with the truck. (unlike my mom's car which turned the blower motor on by itself while i was driving today, and the indicator light for "D4" burned out this morning as well.)

[YotaFun]

Sean I believe the wire pictured is straight from the battery.

I will look at the wiring diagram and my truck when I am a little more coherent
(being sick sucks lol)

[Scuba]

Pretty sure the wire sean has that is corroded does com straight from the alternator.
I was looking at it today and that one looks like it does in fact straight from the alternator.

[Seanz0rz]

FIXED

so today, after finishing the other vehicles for the day (oil changes, etc) i got working on the 4runner.

after removing the battery, i removed the 3 bolts holding the fuse box to the inner fender. i removed the bottom cover, here is what i saw:
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3109.jpg

no evidence of fire or anything, just green dust from the massive corrosion above.

here is the underside of the fuse box. you can tell the "cell" that has melted. this contains the connecting bolt. you can see, no other damage. the fuse box is in serviceable condition.
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3110.jpg
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3111.jpg

at some point, i will acquire a new fuse box and swap it in. until then this one will be OK.

there are two of these things in the fuse box, what the hell are they?
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3112.jpg

so i split the bundle going down from the inner fender to the frame and back up to the alternator. the wire in question goes from the alternator into the fuse box, along with the control/status wires for the alternator, and a black/white wire that goes towards the starter. i separated the small wires from the alternator supply wire, and bundled them back up in split loom.

here is the wire in question:
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3113.jpg

[Seanz0rz]

i dissected it and found that the corrosion had penetrated quite a bit of the wire. the first picture shows the damaged end of the wire, as well as the inspection hole i cut to look at it. the second picture is a close up of this hole:
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3114.jpg
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3116.jpg

i had a 40" 4AWG wire from autozone that i planned on using. the only problem, the factory ends were like tossing a hotdog through a hallway.
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3117.jpg

a couple of #4, 1/4" terminals solved that problem quickly.
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3118.jpg

they were crimped on with a pair of vice grips. i got them as tight as i could.
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3119.jpg

[Seanz0rz]

i started at the alternator, attaching the wire and even the stock cover fit!
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3120.jpg

i brought up the wire through the stock fuse box wire retainer on the right rear of the fuse box, and measured, stripped, and crimped my connection. here it is:
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3121.jpg

the finished fuse box:
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3122.jpg

and everything reconnected. i love my quick disconnect battery terminals, they are great for trouble shooting or disconnecting the winch when i know i wont need it for a while. i am planning on pulling some stumps soon, so it is connected for the time being.
http://i955.photobucket.com/albums/ae38/hamiltonfabrication/Electrical%20Upgrades/IMG_3123.jpg

here is what i think happened:
-the last time i fumbled with the electrical, i may have loosened the nut on the stud where the melting took place. i may have failed to fully tighten it, or it may just have backed out on its own. either way, it was loose when i started working today.

-this loose nut caused a loose, and therefore high resistance, connection between the supply from the alternator and the fuse box.

-this likely resulted in an enormous amount of heat and sparking/arcing occurring within the confines of the box, melting the surrounding plastic, and causing the copper to oxidize extremely quickly, causing even more resistance.

lesson learned: make sure things are tightened properly.

i highly suggest checking all the major connections at the starter, alternator, ground from the block, etc.

[4x4mike]

Good to hear it wasn't too bad. Looks like you're good to go again.