2ToyGuy

I drove my 4Runner into town today. A short, 20 mile jaunt. It ran perfectly, as usual. Got done doing what we were doing, fired it up...ummm...poor word choice, there...anywho, as I was getting in, getting my seatbelt on, etc, I smelled something funny. Like very hot plastic. I got out and looked under, over, and around. I saw a few wisps of light smoke, nothing heavy, but couldn't figure where it was coming from. My wife looked into the cab from the passenger side, and started yelling "FIRE!!". She reached in, and flipped the key off right away.
Anywho, long story short, the fuse block under the driver's side kick panel was on fire. Actually flaming up pretty good. Thankfully, the chiropracter's office are very nice people, and brought out a small fire extinguisher. One brief FFFFFT from the extinguisher and it was all over but the crying. And I was.

Has anyone else had this situation? Fire in the fuse block? I did need to replace the Engine fuse a couple days ago. No idea what caused it to fail, but either I screwed the pooch somehow when I put the new one in, or whatever caused it to fail set fire to the fuse block, somehow. Once I replaced the fuse, I ran it over to the local store, about 3-4 miles away and back, and about 20 miles into town today. No problems, no smoke, no smells, nothing wrong at all.
I did run the back window up and down a couple times, first after I replaced the fuse, and again, at the store to put our stuff in. I did not run the back window at all today. Just started it, let it warm up, drove into town, and after about 35 minutes in the chiro's office, started it up and POOF! Fire.

Any insight, or even good guesses?
Pat☺

RAD4Runner

Sorry about that, Pat.
Why did you replace the engine fuse?
Did you inspect what exactly what part burnt or where it may have started?
Exactly when did the fire start? When you turned ign on? When you cranked? When it went VROOM? If you're using the correct fuses, the fire must have been caused by short to ground before one of the fuses.
Engine fuse supplies these:

swampedout

Im sorry to hear that, Pat. Luckily you have an observant wife. Did you get the fire out before anything else was damaged?

I have a very basic grasp of electrical systems, but if you had properly sized fuses installed, my thought is its probably some corrosion or loose connection causing resistance in the wiring or clips that hold the fuse in. Otherwise, whatever amount of electricity that could start a fire would have blown a fuse.
Im also curious, like Rad4Runner, when exactly the fire started and why it was when you turned the truck back on, as opposed to when you were driving on your way there. Sounds like heat built up enough that when you started the truck, the amperage triggered a fire.
Just some guessing...

Glad you and your wife are ok!

2ToyGuy

Thanks to all for their good wishes. I appreciate it.

What clued me into the Engine fuse originally, was we were unable to move the back window up or down one day. We went to the store, about a 4 or 5 mile trip, it worked fine there, at the store, and when we got home it went down normally, engine still running. When I tried to put it back up, engine running, nothing. I turned the engine off, unloaded our groceries, and went to put the window up. And, since the key needs to be ON to run the window, when I turned to key to ON, no dash lights. No CHECK ENGINE, no OIL, no BRAKE lights, that should be on with the engine off and the key in the ON position. And no rear window movement.
The only thing I found in common to those things was the Engine fuse, so I replaced it. I was using the same FSM schematic you showed, Rad. With a correct amperage, 15A fuse. Standard, automotive, blade type fuse. The one that had failed was the same color, same amperage, not a slow-blow. I think the one I pulled was a factory original. I wasn't able to find out just why the original failed. No burn scents, no magic smoke, everything the fuse feeds worked normally with the new fuse in. The female side gripped the fuse as I would have expected. Not so tight it felt jammed, not loose to where the fuse was flopping around. Snug, I guess the word would be.
I started it up, dash lights worked normally, window worked normally. No odd scents, no smoke, nothing. 3 days later, and it just sat for those days, we went into the main town for this area, a 20 mile trip. I had let it warm up after starting it, before we left, so that my wife would be comfortable. No odd scents, no magic smoke, everything worked normally.
When we got ready to leave town, to go back home again, I started it like usual, standing outside the truck with the Clutch Start Cancel switch engaged. Dash lights came on normally when I started it. We got in, started putting our seatbelts on, etc, as usual, when we got the odd scent, like hot plastic, and a light amount of smoke. There was a fair breeze blowing, so with both doors open, my wife and I looking for the source of the smoke, it was impossible to see where it was coming from. We found it!
My wife reached in and shut the engine off as soon as she saw the fire. Key all the way to OFF. We put the fire out with an extinguisher. Just a short shot from it did the job. I pulled the battery leads off once the fire was out.

I'm wondering if perhaps we got a drop of water in the area of the fuse box. We did have a couple days of rain/snow, after I had replaced the fuse. Snow at night, melt off during the day. I didn't SEE any water in the area when I replaced the fuse originally. The whole area of the fuse box and the wire bundle feeding it were clean and dry. No evidence of any kind of any water intrusion at all. None in the engine compartment upstream the engine fuse, either. Relatively clean, the usual oil, dirt, and dust, and so on that one sees in the engine compartment of a 30 year old truck. I don't steam clean it every day or anything, so the small leaks, from the PCV system, and so on. Totally dry. I was using a good headlight on my thick skull to provide me light when I changed the fuse out, so I could see very well the whole area of the fuse box. I've never seen ANY water in the truck, ever. I realize seals don't last forever, and degrade over time, but mine all SEEM to still be sealing very nicely. Currently.
I didn't see any burnt or melted wires inside the engine compartment, and I looked carefully before I started the truck after I first replaced the fuse.

Thanks again to all for the help, and good wishes. I'm no longer capable of doing heavy truck work any more, so I took my truck to my mechanic. Not only is he a very good mechanic, he's very trust-worthy. He, and his whole crew, love older Toyotas, and they all have at least one themselves. He said he'd seen this happen before, after taking a look up into the fuse box area. He's running behind, at the moment, about 2 weeks, but he'll get to it ASAP.

I'll keep y'all informed when I find out anything.
Have fun, gang!
Pat☺

RAD4Runner

There has to be something that has obvious signs (see, feel, smell) of being bunt/overheated. Lots of plastic to deform/melt/discolor.
Also remember that when loading stuff from store, you would normally open window from tailgate key. That uses the circuit breaker. The console key uses the engine fuse. I have the write-up on how rear window works.
This week I have been hating that stupid P.O.S. idea of a window that needs electricity on a utilitarian truck even more. Many of us store fire extinguisher in the back. Problem like yours wud block ez access to the extinguisher. My problem this week is that while working on truck, I wud have to reconnect battery to stow things at the end of each day.

swampedout

Hmm, I know I said I suspected corrosion but now that I think about it, my 1980 with a 20r had a leaking windshield that dripped on this same fuse box and had lots of corrosion there. For that truck, the only problem was the wipers didnt work until I cleaned the contacts. I dont remember of other fuse contacts were corroded. And obviously, that vehicle has much less electronics than yours.

Then again, I didnt have the wiper switched on for an hour, unlike a different circuit that might have enough amperage flowing while driving that significant heat could build up.

Im thinking about Rad Runners idea of a ground short too. I can see a lot of reasons why this could happen.

If the fire didnt spread too far, and it sounds like it didnt, your mechanic should be able to pinpoint it.

My city has 3 Toyota mechanics, not including the dealership. Seems like its not a bad business to be in these days with how popular Toyotas are.

2ToyGuy

Actually, there is. The entire fuse block, with the 9 active, 2 storage fuses in it, is a crispy critter.
Now the trick is going to be finding the short to ground that caused it. I suspect, however, now that I've thought about it, the trailer pigtail that's on it for towing purposes. No not porpoises, purposes!

Sorry. I'm being silly. I apologize.
I looked, just by happenstance, at the pigtail, which I installed around 2000. It's never given us trouble before, however, it didn't look right. I only saw it for a few moments as the tow truck driver was chaining it down to the flatbed. I have a sick feeling it's worn through one or more wires. It got tucked up under a pair of metal plates on the rear bumper, right where the towing drop hitch attached. Again, I put the drop hitch setup onto the truck shortly after I bought it, back in '99. Welded it right to the frame, as it's designed to be.
Once again, I have a real sick feeling one or more wires wore through, and may touch at random intervals. THAT'S why it would be good for a time, fail something, be good for a time, etc. When my mechanic calls me, and he will, I'll tell him my suspicions.
If that IS the cause, I'm going to feel like a total moron for doing the tucking. I'll also tell him to pull the pigtail. I doubt I'll be doing any towing in the future. I used to use a trailer to take all the "stuff" we needed to go to rabbit shows. Yes, we, my lovely, observant, wife and I once raised, and showed bunnies. Sold them off to people for pets, gave them to 4H kids, and ate the ones that weren't quality enough for any of the other things. YUMMY!
Had a large room for a barn, raise a couple hundred at a time. My kids hated Sunday morning. It was bunny-barn cleaning day. Made the grass in the yard grow like a dream, though.

Yes. I've read, and understood it. It's a great write-up.
Bear in mind, I know electronics/electrics. I spent my entire working life as a radar tech, and head electronics tech, for a US Customs, which became a USAF, Aerostat site. The circuits in a vehicle, especially an older one like our trucks, are MUCH simpler than what I worked on for a living. These circuits are very easy for me. Yes, apparently I screwed the pooch on this one, and I do admit it.

Sorry, I babble. Thanks again to all. More to come.
Pat☺

RAD4Runner

Good to be silly. Great coping technique. I believe Dalai Lama once said, "We either cry about life or laugh about it." It remains what it is.
Yeah, the pigtail could affect both the taillight and the blinker relay circuits.

And Re: rabbits... we jokingly say, in America they do not eat dogs because they are pets. In the Philippines we (for real) do not eat rabbits because they are pets

2ToyGuy

I remember that. I spent more than a month at Clark AB, in Angeles City. Beautiful place. I must have gained 5 lbs while I was there, even though I excersized my tail off, when not at work. The food was just too good for me to resist. Both in the chow halls, AND the street vendors. If I hadn't worked out so hard, I would have gained a lot more!
It didn't help that I moved in with a couple of Air Force girls, that lived across a parking lot from one of the chow halls. I ate like a pig in that place. Those locals they hired to be cooks are GOOD! It was better than staying with another Marine, in a small room, in a condemned barracks, that's for sure!
Most of us would spend their off time out in town, getting drunk, partying, hooking up with the local bar girls. Not me! The two Air Force girls I stayed with were enough for me

Take care all, and a very happy new year, I hope, to you all!
Pat☺

maxvp01

Maybe it was your fuse block itself? The interior fuse block in my 89’ 3VZE pickup ended up being bad. I still had 12.6V going to my taillights, but they did not light because the amperage was not there. My guess is the built up resistance would not allow for it.

I found the fuse block was starting to melt right where the fuse plugged in. I also opened up the block but everything inside looked normal.

Maybe you had a similar issue started to occur?

2ToyGuy

Hi Max!
Good idea to take a look at that, but unfortunately the entire block burned up. I mean it's now nothing but a crisp, black, chunk of plastic ash, with the wires that used to be fuses sticking out in spots. Not the wires TO the fuses, but the small pieces of metal inside the fuse plastic piece. The thing you replace when the fuse blows.

It's going to either need a replacement fuse block, the thing you showed in your picture, or one someplace else. A commercial fuse block, wired to have fuses of the same amperage in the same circuits, as before. Not an easy project for sure.

I trust my mechanic implicitly though. He said he's seen this before, so I have faith in him. His labor costs are a little up there, but he never overcharges me for what his guys do. I trust him. He will also fix anything his guys do wrong for free. You should have seen what the amateur he hired, who worked on my truck before, did. All the vacuum lines were left off, the battery was dead, the alternator bad, and so forth, when I got it back. I pointed it all out to him, and it was fixed that day, for free. He even paid for the tire the little punk had stuck a screwdriver into the sidewall of, because I had dared to point out his colossal screw-ups.

Thanks for the good idea. I wish it was as easy as cleaning the contacts, I really do!
Pat☺

maxvp01

Wow, glad you have a good mechanic to take a look at it! It’s getting pretty hard to find a good mechanic who is honest nowadays. There’s only two guys I trust down here in NC for auto repair.

One actually specializes in old toyota trucks and it’s all he works on. Not only that but he has 70+ parts trucks he parts out! The other shop is great with everything, especially diagnostics!

Cant tell you how many places tried to rip family off for just basic stuff.. One shop tried charging my dad $400 to put a battery in and change terminals..

Well glad you and your wife are okay, and the truck is in good hands! Good luck with it!

2ToyGuy

Thanks for the good thoughts! We appreciate it.

Pat☺