White-Blue is the main 12v feed wire from the ammeter (basically everything goes through that wire).
What colour is the wire leaving that box? Just plain red?
Wiring Nightmare
- Thread starter Joe45
- Start date
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What colour is the wire leaving that box? Just plain red?
I think what has happened here is that the solid red wire (connected to the rectangular thingy) is the 12v feed to the headlight circuit.
It used to be connected to the fuse box (should be 20A not 30A) but the wire snapped off at some point.
Maybe the rectangular thing is a resettable fuse or something like that.
So I guess that the horrendous white blue hack job needs removing, and the red wire needs soldering back in place onto the fuse box. (My guess without having tested it!!)
What I did is this - remove all fuses to avoid confusing your tests.
Now figure out which each one should be on the diagram and draw them out however it makes sense to you.
You can see what colour wire should go to it, and which circuits it should feed.
Now get your meter and test resistance between the fuse and the destination (for example, between the headlight fuse and the headlights should be around zero ohms with the switch on).
If you don't have continuity then something isn't right.
- Thread starter
- #43
Yes. Just red.
- Thread starter
- #44
OK so I cleaned the fuse box connections with sandpaper wrapped around a little pole.
I then went ahead and put liquid tape and then regular tape around the red wire that had been stripped for that splice.
I tested the rectangular box thing and it has something to do with the headlights, as you said. When connected the headlights work. When not connected, the headlights don't work. The strange thing though is that there is power to both of the connection points on that box with ignition on or off.
I moved the power wire for the flasher to that stripped wire point on the fuse box. It has previously been just wrapped around a fuse end.
Everything else stayed the same.
I tested it and now the headlights and blinkers work-front and rear, but the hazards only work in the rear. And now the back-up light doesn't work, and the running lights don't work in the rear.
The truck started fine.
Then it caught fire.
No kidding. It caught fire.
It was under the dash: huge white smoke billowing out from under the dash. So I ran to the batteries and yanked off the negative cable.
No fuses were blown, so I have to think the issue is before the fuse box, but who the hell knows. The wiring is so rigged up it could be anything.
- Thread starter
- #45
Here are a couple of pictures.
It seems the rectangular box started to melt, as did the loom overhead.
I taped everything up with extra care. I can't figure out what the hell happened.
It seems the rectangular box started to melt, as did the loom overhead.
I taped everything up with extra care. I can't figure out what the hell happened.
Holy sh!t.
That's not what you want to see. That is because somewhere, somehow, that white-blue wire got sorted to ground.
Hope it's not as bad as it looks.
This is what the fusible link is there to protect against normally
- Thread starter
- #47
I can't go any further short of rewiring the whole damn thing. Trying to figure this mess out is just beyond me with all the hack jobs whatever POS SOB did this disgusting mess. At least with rewiring I can start with a fresh slate and go one step at a time.
Thing is, no way I can rewire this truck until I have a garage. It's already cold. 37 degrees this morning. Forecasting high 20's in the next day or so. I am also illustrating a comic book and a series of 11 kid's books. I enjoy some of the tinkering and figuring things out, but this is a total FUBAR situation.
I have an interview day after tomorrow and now I need to borrow a vehicle, which sucks.
Another option is have it towed to my mechanic to sort out, but with the burned out loom there, I am wondering if it's going to be a major issue-require total rewiring plus cost of labor. Maybe he can just patch it up. I don't know. At least he can give me an estimate... but seems like this would be very expensive with a mechanic.
I'll have to think on this.
I am both depressed and livid beyond words right now. What kind of A$$h*le does this kind of crap? I mean, I can understand patching something up, but this was not giving a crap and just throwing it together not caring about someone being hurt or a serious fire.
I've had experiences in the past with these scumbag backyard "mechanics" and they always, ALWAYS, messed things up-which is why I wound up doing everything to my old CJ from rewiring it to swapping out a newer 4.0 after a mechanic blew it by sitting there and flooring it until I ran over and yelled at him to stop.
Sorry for the rant but I feel like finding whoever did this and knocking his teeth out.
Thanks to you all for all the help. I appreciate it.
Thing is, no way I can rewire this truck until I have a garage. It's already cold. 37 degrees this morning. Forecasting high 20's in the next day or so. I am also illustrating a comic book and a series of 11 kid's books. I enjoy some of the tinkering and figuring things out, but this is a total FUBAR situation.
I have an interview day after tomorrow and now I need to borrow a vehicle, which sucks.
Another option is have it towed to my mechanic to sort out, but with the burned out loom there, I am wondering if it's going to be a major issue-require total rewiring plus cost of labor. Maybe he can just patch it up. I don't know. At least he can give me an estimate... but seems like this would be very expensive with a mechanic.
I'll have to think on this.
I am both depressed and livid beyond words right now. What kind of A$$h*le does this kind of crap? I mean, I can understand patching something up, but this was not giving a crap and just throwing it together not caring about someone being hurt or a serious fire.
I've had experiences in the past with these scumbag backyard "mechanics" and they always, ALWAYS, messed things up-which is why I wound up doing everything to my old CJ from rewiring it to swapping out a newer 4.0 after a mechanic blew it by sitting there and flooring it until I ran over and yelled at him to stop.
Sorry for the rant but I feel like finding whoever did this and knocking his teeth out.
Thanks to you all for all the help. I appreciate it.
That makes sense. It's powered directly from the white-blue so if it's a fuse then you'd expect power both sides of it.
The flasher should be powered through the hazard switch which switches the feed from the turn fuse to the stop fuse when the hazards are switched on. Normally the turn signals don't work with the ignition off.
probably disturbed a connection at the hazard switch I guess. No big deal.
Backup light runs from the heater fuse along with instruments - possibly a loose fuse or connector.
- Thread starter
- #49
I think the hackjob is so bad that the only real way to get it running is to rewire the whole damned thing. Who knows what else is all mixed up and jumbled togewther.
Thing is, figuring out what goes where with the rewire. I feel overwhelmed at the moment.
It probably seems like a massive deal right now, but it might not be a huge job to repair if you're lucky.
You need to start at the burnt part and unpick the tape.
Hopefully you haven't melted every single wire for the whole length of the harness.
Hopefully you've only melted one or two wires for a foot or so, which is then easy to repair.
You think yours is bad. This is the superfluous cable I removed from mine in the first week...
If I was nearby then I'd come and help you out but AZ is a bit of a trek from UK.
Wow you should rename that thing Tesla, Eloon will be so happy.
Back in the day the little metal box thingy was an automatic circuit breaker that would reset itself when it cooled down - that way your headlights would blink on/off so you could get shut down and pulled over with some light instead of no light when a fuse blows.
I'm at the point where I'm just going to rewire mine. Two weeks ago I had one rear running light, it would start and run plus the front heater fan would work, I checked the fuses all were good. Two day ago, when I step on the brake, both turn indicators light up. It all worked back in 2010 when it was parked. I'm toying with the idea of drawing it up in AutoCAD.
Back in the day the little metal box thingy was an automatic circuit breaker that would reset itself when it cooled down - that way your headlights would blink on/off so you could get shut down and pulled over with some light instead of no light when a fuse blows.
I'm at the point where I'm just going to rewire mine. Two weeks ago I had one rear running light, it would start and run plus the front heater fan would work, I checked the fuses all were good. Two day ago, when I step on the brake, both turn indicators light up. It all worked back in 2010 when it was parked. I'm toying with the idea of drawing it up in AutoCAD.
- Thread starter
- #53
Holy Crap!
- Thread starter
- #54
That's what I think. Trying to sort out all the mess can become a total nightmare compared to just starting with a clean slate.
- Thread starter
- #55
You may be right. I hope you're right.
I'm gonna see if the mechanic can at least patch her up so I can drive. If he can, I will rewire completely later on.
If he can't, depending on his charge for rewiring it, I will either give him a go ahead, or have it towed back to my yard where it will sit until I can get a garage up and do the rewiring.
Give it a go unpicking it. At least you'll see the extent of the damage before asking for a price.
I fried one of my austin mini harnesses with similar smoke theatrics. I know it sucks.
Mines a few years older than yours but yours looks in pretty good shape tbh.
Problem is that you get one PO kept blowing headlight fuses so bodged on a circuit breaker, and another PO added a cigarette lighter, and before you know it, you have a Christmas tree of crap to unpick, all of which is a potential fire hazard. Luckily it didn't catch fire.
Getting that back to original probably only needs pulling out a handful of wires, and replacing 10 or 15 terminals and the odd burnt bit.
Try not to be too disappointed. By the time you've fixed this, you'll understand the whole thing inside out and be able to fix it at the side of the road with just a pen knife.
This, in my view, is one of the huge benefits of having a 40.
- Thread starter
- #57
Yeah you have a point there.
I was sitting and thinking of how simple these vehicles are, really. Electrics are not my strong point, but I try to see it as positive and negative flowing in a loop: close the loop and you have either energy used to make something move or light up, or it causes heat and a fire. Don’t know if that’s silly or what, but kind of like how I see it.
I just don’t know how these particular loops are supposed to go. And not having a place to work right now-or my second vehicle, makes it very difficult to do anything because I can’t just take my time and walk away for the night.
Working outside, in the cold especially, is miserable for me-done it too many times and I am no longer 20 years old.
The diagrams totally confound me, so I will likely eventually do my own version once I rewire.
I’ll see what I can figure out and keep y’all posted.
Thank you!!!
I'll try to help get you started on the diagram...
I think this one is correct for your year.
The battery is buried in the middle-left (Red).
The ignition switch is at the top left corner - each switch position puts power onto a different wire as shown in blue text.
Generally power (+12v) runs across the top of the page, and ground is at the bottom (green).
I've highlighted the blue-white wire for you in blue.
The big rectangular box running across the top of the page is the fuse box.
Each fuse has power to it at the top (either direct from the battery, or via the ignition switch).
If the fuse is intact, it then feeds whatever is below it with 12V.
As an example I've highlighted the headlight circuit in red on the far right.
The physical location of these wires and components is not captured in the diagram.
Think of electricity in wiring as you would water in a pipe.
Voltage = Pressure. Current = Flow rate, and Resistance = A restriction in the pipe.
A battery is like a pump, creating pressure in the circuit.
A switch is like a valve that allows the current to flow.
The difference is that when you cut a wire (open circuit) your Current can't leak out, so every cut wire is more like a capped off pipe.
I found this analogy helpful when I was learning 40 years ago, and I still use it from time to time for clarity now.
I think this one is correct for your year.
The battery is buried in the middle-left (Red).
The ignition switch is at the top left corner - each switch position puts power onto a different wire as shown in blue text.
Generally power (+12v) runs across the top of the page, and ground is at the bottom (green).
I've highlighted the blue-white wire for you in blue.
The big rectangular box running across the top of the page is the fuse box.
Each fuse has power to it at the top (either direct from the battery, or via the ignition switch).
If the fuse is intact, it then feeds whatever is below it with 12V.
As an example I've highlighted the headlight circuit in red on the far right.
The physical location of these wires and components is not captured in the diagram.
Think of electricity in wiring as you would water in a pipe.
Voltage = Pressure. Current = Flow rate, and Resistance = A restriction in the pipe.
A battery is like a pump, creating pressure in the circuit.
A switch is like a valve that allows the current to flow.
The difference is that when you cut a wire (open circuit) your Current can't leak out, so every cut wire is more like a capped off pipe.
I found this analogy helpful when I was learning 40 years ago, and I still use it from time to time for clarity now.
- Thread starter
- #59
Awesome!
Thank you!
from Land Cruiser manuals, FSMs, and repair resources - https://heritagecruisers.com/pages/manuals
The 1975-1983 FJ40 Chassis Body Repair Manual (98154) has (at least my opinion) the easiest to read diagram I'm aware of. Unfortunately only covers several years, and comparing against 1970-1974 Land Cruiser Chassis & Body Repair Manual (98077) (mine is a '74) it's mostly close enough I just use the '75 diagram.
Unfortunately it crosses multiple pages, but is still easier to read...
The 1975-1983 FJ40 Chassis Body Repair Manual (98154) has (at least my opinion) the easiest to read diagram I'm aware of. Unfortunately only covers several years, and comparing against 1970-1974 Land Cruiser Chassis & Body Repair Manual (98077) (mine is a '74) it's mostly close enough I just use the '75 diagram.
Unfortunately it crosses multiple pages, but is still easier to read...
