Melted Wires behind Fuse Panel: Real Time Help. Headlights, Horn, blinkers, hazards, door beep not working.

[Beehanger]

Burnt spagetti wire fun! The melting shown in the two picks doest seem to go further into the harness. just whats shown in photo. If anyone is good with electrical input appreciated. The plastic clip shown in the first and last pictures was a loose and unclipped, I have no clue where its supposed to go after looking intensively. It could have totally grounded itself.

Context: I Was going to drive the rig home today the 2.5 hours and couldnt get the headlights working. In fact I found the horn, blinkers, hazards, door beep (except when WIPER relay is pulled (WTF?) aren't working either. They were working before, although the headlights would intermittently shut off. Replaced the alternator and some split wires throughout the engine bay, including the black plug by the charcoal canister, and one by the headlights. Its only after turning the rig on after 2 weeks of work regarding steering box and basic electrical repair that all 5 of these components stooped working as well.

Engine grounds and other Grounds looks good (along with one for radio etc), fusible link looks good. no fuses blown.

Ive had melted plastic around the tailight fuse since I bought the truck. The PO (total dumbass based on the state of this rig) stuck a 30 amp fuse in there and the taillights work so i didn't dig in further. Part of me thinks this happened a while ago, and maybe has gotten worse? Or the new alternator (which IS working, rig runs fine etc) somehow exacerbated the electrical problem due to proper charging? (my last alt was going out.)
Lucky I Happened to notice these wires were cooked, along with the wires going into the tail light fuse. Weirdly though,
taillights work perfectly fine BTW

QUESTIONS :
1. How does one fix this, and where can I replace this plastic piece? Im assuming cut the wires back to the unburnt section, and find something similar at O'Reillys in terms of plastic piece? Does order of green wires matter when I reinstall?
Dash is off, gauge cluster out.

2.I also have melted plastic on the fuse panel, just in the taillight fuse. Confirmed, only some of the fuses getting voltage, but some of the ones that are getting voltage dont work and some that arent getting voltage DO work. strange. Does this mean I should replace the whole fuse panel? NLA?

3. I cant seem to find it on the wiring diagram Im not great with electrical but the farm mechanic on my familys farm is helping me is passable at electrical stuff, so a good diagram is appreciated. (photo 5 is what I have found so far.)

Fresh Rebuild, rig ran and drove, just had intermittent startup issue and headlight issue that I assumed was related to the alternator going out (voltage didnt increase upon revving motor on alternator) Hard to know if my issues are interlinked and if the melted wires is the culprit.

Need to get back on the road ASAP, been up late tonight getting the dash off, troubleshooting appreciated. Can be responsive, if anyone can talk over facetime briefly that may be needed, this is a weird one is a bit beyond me.

Thanks a bunch.
Best,
Dan

 

[kevin in okinawa]

my sparky knowledge is limited, but I hope you get it sussed out.

 

[Skreddy]

You have a short somewhere that caused that. To find it, you need to look through ALL the circuits that are affected. Most likely, it’s not a wire in the loom, but a connection somewhere or a spot where the wires go through a place like the firewall or along a spot they can be chaffed, pinched, or burned through.

What year you have would help, pretty sure it’s a 60 and not a 62 series. Here’s the link to the wiring diagram for an ‘83 60.

FSM - 1983 Electrical Wiring Diagram, 36679A

forum.ih8mud.com

I mean this in a, um, constructive way? Your posts always really ramble with lots of side information that makes it really hard to understand what and where your problem is.

Based on the poor pics and long description, I’m going to say your burnt wires are in the dash behind the gauge cluster on the far left side like fuse block? The impacted circuits are wipers, lights, horn from your description and the color of burnt wires. Looking at the pics I see a red wire wrapped around sharp metal where the tilt column spring goes. There’s a vampire tap on the red/blue wire that goes to? The wiring for aftermarket radio looks like a cluster of ***s. All of these are potential issues.

First you need to pull every fuse and check them with an ohmmeter or just replace them. Ensure every fuse is the correct amp rating for the circuit. Then check all bulbs, may as well just replace them, and check the bulb sockets for corrosion.
Those wires likely burned because too large of a fuse was used and when they shorted, the wire became the fuse instead of the fuse itself.

 

[OSS]

Headlights, Horn, blinkers, hazards, door beep all ground together at a common junction behind the dash. Most likely that ground junction (looks like a plug) is fried too.

 

[Skreddy]

The wires going into the fuse block that are fried are same circuits as at the plug. If there is a 30 amp fuse for tail or brake lights, I’d start with that circuit as those (and horn) should be 15 amp fuses.

 

[OSS]

What can happen with these old cars is ... If a higher power accessory is installed, (most commonly higher wattage headlights or a high powered music system tapped off of original wires) the increased current running through the inadequate wire size creates excessive heat at a connector interface. Over time (years perhaps) the constant cooking inside of the connector burns plastic which can deposit contaminates on the metal to metal contact.
This creates even more resistance at the connector which creates even more heat --- etc... until you get a melt down as you've experienced.

It happened to me on my FJ60. My culprit: high wattage headlights installed on original wiring harness.

 

[Beehanger]

Headlights, Horn, blinkers, hazards, door beep all ground together at a common junction behind the dash. Most likely that ground junction (looks like a plug) is fried too.

Is that the plug shown in my first and last photo? where should it ground.

 

[Beehanger]

What can happen with these old cars is ... If a higher power accessory is installed, (most commonly higher wattage headlights or a high powered music system tapped off of original wires) the increased current running through the inadequate wire size creates excessive heat at a connector interface. Over time (years perhaps) the constant cooking inside of the connector burns plastic which can deposit contaminates on the metal to metal contact.
This creates even more resistance at the connector which creates even more heat --- etc... until you get a melt down as you've experienced.

It happened to me on my FJ60. My culprit: high wattage headlights installed on original wiring harness.

Appreciate this. Had the OEM Koito H4 put in 2 months ago. Are these considered higher powered? I smelled burning plastic feintly in the cab about 4 months ago.

 

[Beehanger]

You have a short somewhere that caused that. To find it, you need to look through ALL the circuits that are affected. Most likely, it’s not a wire in the loom, but a connection somewhere or a spot where the wires go through a place like the firewall or along a spot they can be chaffed, pinched, or burned through.

What year you have would help, pretty sure it’s a 60 and not a 62 series. Here’s the link to the wiring diagram for an ‘83 60.

FSM - 1983 Electrical Wiring Diagram, 36679A

forum.ih8mud.com

I mean this in a, um, constructive way? Your posts always really ramble with lots of side information that makes it really hard to understand what and where your problem is.

Based on the poor pics and long description, I’m going to say your burnt wires are in the dash behind the gauge cluster on the far left side like fuse block? The impacted circuits are wipers, lights, horn from your description and the color of burnt wires. Looking at the pics I see a red wire wrapped around sharp metal where the tilt column spring goes. There’s a vampire tap on the red/blue wire that goes to? The wiring for aftermarket radio looks like a cluster of ***s. All of these are potential issues.

First you need to pull every fuse and check them with an ohmmeter or just replace them. Ensure every fuse is the correct amp rating for the circuit. Then check all bulbs, may as well just replace them, and check the bulb sockets for corrosion.
Those wires likely burned because too large of a fuse was used and when they shorted, the wire became the fuse instead of the fuse itself.

Roger that. You're right on with the location. It's all behind the fuse panel, the first photo is against the back area above the steering assembly.
Aftermarket radio wiring is a bit tangled, I can clean it up.t The mechanic helping me had used existing wiring from the PO, we just threw the new radio in. Just a typical Sony Head unit, not higher powered. No fraying there that I could see.

More context:
Only some of the female locations on the fuse panel are getting power, likely from these messed up wires. Wierdly, the taillight one is still getting of power.
Koito h4's installed 2 months ago. had burnt plastic smell 4 months ago coming from the dash area.

My plan based on what you guys have said so far is to:
1. Look into where the harness goes through the firewall and see if there's frayed wires there.
2. Replace all fuses.
3. Look elsewhere in the truck a second time for frayed wires grounding out.
4. Find another plastic clip (ground junction) that will work from the auto parts store.
5. cut out all melted wire an inch past the melted area and add new wire.
6. Move negative battery ground from side the engine head to engine mount nut.
7. Start it up and see if this fixed the issues.

Questions:
Are the melted wires likely the source/manifestation of why the headlights, horn etc aren't working? With a short being the original cause? Which hopefully my family's tractor mechanic fixed last week during engine bay electrical cleanup day (fixed/replcad any broken wires we saw in headlight area)

Could the grounding plug being all loose when I found it be the source of a problem as well, as in it wasnt really touching metal or clipped to anything.

Does order matter for plugging wires into ground junction? I've already cut the ground junction out at the base to take into Oreillys for a replacement.

Is my thinking sound on taking action, am I missing anything so far?

How long should I expect the process to take?

Should I order another fuse panel?


Apologies for ramblings earlier, working on that.

Tackling again in a few hours. If this is beyond the scope of the forum, I can pay anyone to facetime as well if its easier to explain that way, I have a lot of IOU coupons and a mechanic with me today . We would be all ears..... Need this done for work. 208 309 4623

Thank you guys,
Dan

 

[Skreddy]

Check the koito wiring for shorts too. I worked on one that they passed the loom through one of the inner fender holes near the battery and it had rubbed through and was shorting the wire. This was blowing the fuse but if you had a higher rated fuse it might melt wires instead.

 

[Beehanger]

Check the koito wiring for shorts too. I worked on one that they passed the loom through one of the inner fender holes near the battery and it had rubbed through and was shorting the wire. This was blowing the fuse but if you had a higher rated fuse it might melt wires instead.

Okay Ill check. There was some questionable wiring on the existing harness, mainly just old red wires by the drivers side healight. ill take a picture to show you when im at the truck in a few.

 

[cruisermatt]

Unfortunately that harness is likely completely toast if that’s the damage you can see. There’s probably way more that you don’t see.

And something had to cause that.

 

[Beehanger]

Unfortunately that harness is likely completely toast if that’s the damage you can see. There’s probably way more that you don’t see.

And something had to cause that.

 

[Beehanger]

Unfortunately that harness is likely completely toast if that’s the damage you can see. There’s probably way more that you don’t see.

And something had to cause that.

s***, gotcha.

Cut into the wiring harness outer tape, didnt look like the actual melting cancer spread. all the green wires looked okay under there.

The wires feel supple and not brittle further in the harness, hoping I got lucky.

But youre saying theres probably more melted wires somewhere or the damage is internal from it shorting out along the whole harness? Could I visually see this or test it with the brittleness of the wires/ with a multimeter?
Thanks a bunch,

Dan

 

[Devils Paw 80]

Appreciate this. Had the OEM Koito H4 put in 2 months ago. Are these considered higher powered? I smelled burning plastic feintly in the cab about 4 months ago.

I don't think so.

 

[Coolerman]

First: I am not familiar with the FJ60 wiring, so the following statement may be incorrect. Someone more familiar with FJ60 wiring correct me if I am wrong.

Second I responded to your email with the part # and price for that 6 pin female connector.

That "junction block" appears to be a 6 pin female latching connector (My Part # FLF6P6.3W) with a shorting block plugged into it shorting all 6 pins together. I don't think that is a grounding block. Toyota uses White/Black for ground wires, I believe that is a juction block to distribute +12V to the park light wires, the tail lights, the headlight cleaner relay, the clock light, and the dash light rheostat. If that shorting bar touched ground, that would explain why ALL those green wires appear to be melted. Once repaired you should tape that up really well to prevent it from shorting again.


Now that massive short alone MIGHT explain why your headlights, blinkers and hazards are not working, as the shorted wires may have melted into other circuit wires. However those could also be separate issues.

I would start by repairing ALL the damaged wires, replacing the connector block only if it's melted, installing the proper size fuse for the tail lights, then take one circuit at a time and start trouble shooting.

The suggestion about replaceing ALL the fuses is a good one. I would also spray contact cleaned or use DeOxit on all the fuse terminals.

Next I would find every where there is a ground connection to metal, remove that connection and clean the ring terminal, the bolt, and the place it threads into of all corrosion. Reassemble and coat it with liquid tape to seal it from future moisture.

Next I would make sure that ALL the light bulbs are good and the contacts for the bulbs in the sockets are cleaned. Bad gounds at the light housings can drive you nuts as electricity takes the path of least resistance and that sometimes will be through the bulb elements if the ground is bad. This shows up for example as the park lights dimmly lighting up when you press the brake pedal making you think there is a short when in reality you are missing a ground.

Make sure the flasher is actually good since both Hazards and Turn Signals do not work.

The headlight fusible link also powers the fuse that protects the Turn Signals, the Hazard Switch, and the Horn. The link may look good but be bad or intermittent. I can rebuild the fusible link if it's bad. You would need to send me the link so I can re-use the old connectors.

Check to make sure you have power on both sides of the Hazard/Horn fuse. If not then the fusible link is bad.

I know that's a lot to digest but these older trucks can be challenging to trouble shoot with all the variables involved.

 

[Beehanger]

First: I am not familiar with the FJ60 wiring, so the following statement may be incorrect. Someone more familiar with FJ60 wiring correct me if I am wrong.

Second I responded to your email with the part # and price for that 6 pin female connector.

That "junction block" appears to be a 6 pin female latching connector (My Part # FLF6P6.3W) with a shorting block plugged into it shorting all 6 pins together. I don't think that is a grounding block. Toyota uses White/Black for ground wires, I believe that is a juction block to distribute +12V to the park light wires, the tail lights, the headlight cleaner relay, the clock light, and the dash light rheostat. If that shorting bar touched ground, that would explain why ALL those green wires appear to be melted. Once repaired you should tape that up really well to prevent it from shorting again.


Now that massive short alone MIGHT explain why your headlights, blinkers and hazards are not working, as the shorted wires may have melted into other circuit wires. However those could also be separate issues.

I would start by repairing ALL the damaged wires, replacing the connector block only if it's melted, installing the proper size fuse for the tail lights, then take one circuit at a time and start trouble shooting.

The suggestion about replaceing ALL the fuses is a good one. I would also spray contact cleaned or use DeOxit on all the fuse terminals.

Next I would find every where there is a ground connection to metal, remove that connection and clean the ring terminal, the bolt, and the place it threads into of all corrosion. Reassemble and coat it with liquid tape to seal it from future moisture.

Next I would make sure that ALL the light bulbs are good and the contacts for the bulbs in the sockets are cleaned. Bad gounds at the light housings can drive you nuts as electricity takes the path of least resistance and that sometimes will be through the bulb elements if the ground is bad. This shows up for example as the park lights dimmly lighting up when you press the brake pedal making you think there is a short when in reality you are missing a ground.

Make sure the flasher is actually good since both Hazards and Turn Signals do not work.

The headlight fusible link also powers the fuse that protects the Turn Signals, the Hazard Switch, and the Horn. The link may look good but be bad or intermittent. I can rebuild the fusible link if it's bad. You would need to send me the link so I can re-use the old connectors.

Check to make sure you have power on both sides of the Hazard/Horn fuse. If not then the fusible link is bad.

I know that's a lot to digest but these older trucks can be challenging to trouble shoot with all the variables involved.

This is a wealth of knowledge. Thank you very much.

I have pigtails coming for the areas in question from Barnyard cruisers as we speak. (See photos) the whole fuse box with attached wires is the same wiring as mine.

I’ve got burnt section on the outer plugs on the fusible link, I’ve already replaced it last year, but the truck will still not start every now and then. I replaced the alternator last week before firing it up to fix this issue. But I may have bad grounds etc, as you said.

I have a feeling this damage occurred during prior ownership and he just didn’t tell me. He had a 30 amp fuse in tail light fuse… when it should be 15.

There could be more broken wires I can’t see, I know mice can get up into these rigs. I have one nesting under my fuel tank as we speak. I’ll test light/ continuity test everything after I hook it all up.

The link passed the beep test (setting it to Ohm reading on multimeter and sticking the probes on either side) on one side, but only half the time other side. Can’t remember which. So maybe it has an intermittent problem. I tried sending 2000 ohms through and it would show a number erratically every now and then. I’ll email you about getting the link rebuilt, I’m assuming this is disconcerting.

As for the blank connector block, does the order of the green wires matter? I cut mine off to examine it, and like I said have another with wires attached (a pig tail as they say) coming in the mail. Do you mean tape the metal section so it can’t ground, or just tape it to the meat of the harness, or both?

 

[Coolerman]

Junction Block
It does not matter what position the wires are in on the junction block connector. They are all being tied together anyway.

Fusible Link
If you have burnt connectors on the fusible link, and can buy a new one, I would buy it. Burnt connectors will not hold the terminals tightly. This can result in the terminal pushing out of the connector when you connect it to its mate. That results in the terminals not being fully engaged and the overheat problem starts all over again. Also use dilelectric grease in the new fusible link connections to keep the terminals from oxidizing leading to over heating.

Splicing in another fuse panel
Again showing my ignorance of FJ60 wiring but are the fuse block terminals easily removable and are there replacement terminals available? If so it would be a hell of a lot easier to just remove the fuse block terminal that has the melted wire and replace with a new terminal and section of wire than to splice in a whole different fuse panel.

If you decide to splice in a used fuse panel...
Splicing wires
Splicing wires together correctly is not rocket science, it is a learned art. You basically have three methods not counting just twisting the wires together with wire nuts....

Method 1 Splice Crimps
Toyota used what are called splice crimps to make splices inside their harnesses. These are U shaped pieces of stamped brass that come in several sizes for splicing different wire gauges together. You first slide a 1" long piece of heat shrink over one of the wires. Now strip the ends of the two wires to be spliced about 1/4". Put the splice crimp into the crimp tool and hold that with one hand. Then put the two wires together in the bottom of the U (one coming in from each side of the tool) with your other two hands, then crimp it down. Center the piece of heat shrink over the splice and use a heat gun to shrink it down and melt the adhesive making an air tight seal. That's a lot of splices and those 10ga wires can be a pain to crimp that way as they require extra large splice crimps and a larger crimp tool.
The crimp tool is expensive. Mine cost $156.00 but will do up to 10ga splices.

Method 2 Solder and heat shrink tubing
You will need a 200W or better soldering gun to solder two 10ga wires together. Use dual wall heat shrink (adhesive lined) to cover the solder joints.
The is pretty fast and anyone can do it. Most already have all the tools. The one issue to be aware of is old wires can be difficult to accept solder if only using rosin core solder. I have had to resort to using Muratic or Sulpheric acid on really bad wires to clean off the corrosion to good copper. Flush with plenty of water to neutralize the acid and DRY the wire before soldering!!! If the wire looks black after stripping off the insulation then it needs cleaning before the solder will stick.

Method 3 Butt connectors
There are many types of these connectors. Cheap Insulated ones have the Red, (18-22 ga) Blue, (16-14ga) and Yellow, (12-10ga) plastic coverings. I personally hate these things as they don't seal the connection and just look cheap. Also if used where the wire can flex it will break the wire right where it goes into the end of the butt connector.
Better butt connectors are also color coded as above but have built in, dual wall heat shrink tubing to allow for sealing the connection. You crimp it first then heat with a heat gun to shink the tubing to make the seal. These can be a bit bulky so if you use them stagger the splices so you don't end up with a massive bulge of splices.
There are also uninsulated butt connectors available in the same three sizes and these require dual wall heat shrink tubing to cover them for insulation and sealing purposes. They do make a smaller splice than the other two butt splices
Butt connectors are by far the fasted and cheapest method as the tool is pretty cheap and the butt connectors even cheaper.

Note: I do not sell any of the above mentioned connectors or tools.

 

[Michael Hanson]

I’m fighting the same problems. Not easy but doable.With antique cars this is very common. Check all electrical and I mean all. Tail lights,interior lights,trailer lights etc. Most are needing repair.

 

[Michael Hanson]

I’m lucky my son is an electrical engineer.