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Underhood fuse box

This is a 1985 Toyota 4x4 Pick up.
The ‘idiot’ lights on the instrument panel had started to blink on and off sometimes. I took truck to local parts store and had them test the battery and alternator. They said the battery was charging so they assumed the battery and alternator were ok.
Yesterday the truck didn’t want to start.
The battery would not start the truck so I checked battery with my meter. With motor off it showed 9.45 volts.
The ‘smaller’ red positive wire from battery somehow touched and burned into a wire coming from the fuse box underneath the hood. They were kind of melted together, with both having a small skint place where they were touching.
There is something that looks like a butt connector connecting the small positive red wire and a black wire coming from the under fuse box.
I got them a part, put electrical tape on both wires where they were showing bare wire. Then I put the battery on my trickle charger to charge.
Would these two wires touching each other bare wire to bare wire cause them to melt together and cause the battery to lose charge plus idiot lights to blink on and off, even though they are going to the same place/fuse[?] in under hood fuse box?

Well, wires shorting together could definitely cause something to melt. Just b/c two wires appear to be going to the same location doesn’t necessarily mean they connect to the same point in the circuit, and so must be kept separate. It sounds like you indeed had a short circuit that drained your battery. Very few engines would crank & start with a battery charged at 9.45 volt. What you’ve got to do is fix the wiring problem, charge the battery (it should measure close to 12.5 volts even after sitting overnight) with the engine off. During cranking the battery should still measure at least 11 volts, otherwise you may hear a click but not that rrr rrr rrr sound.

To do this repair yourself you’ll need the car’s wiring diagrams probably. If you don’t have those, or don’t know how to understand them, best bet is to take it to an auto-electric shop and ask them to take a look. The solution may be something very simple and for $50 you’ll have it fixed. It might cost considerably more however, if the fuse block needs to be replaced.

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That small red wire is actually a “fusible link”, a fuse, and that melted look is how it’s supposed to let you know it’s burned. The real question is “why did it burn”. To answer this question you’ll need a reputable shop. Something is causing too much current draw, and it’ll take some looking with a meter and a schematic to determine what.

Caution: do NOT replace that link with a piece of wire. It’s there to protect your car’s operating circuits, and replacing it could result in a fire. Once the cause is determined, it’ll need to be replaced with another fusible link with the proper current rating.


The ‘idiot’/‘warning’ lights are still coming on for several seconds sometimes. Any ideas on fixing this problem?
They are the ATF OIL TEMP, BRAKE, and BATTERY warning lights. When this happens the RADIO will cut OFF, and then turn back ON.

Yup. Diagnose the reason for that failed fusible link you described above and change the link.
What you’re seeing is the melted link intermittently connecting and then disconnecting. I’ve seen this before.

The heavy red wire feeds only the starter motor, and is there to allow the necessary current to start the car without blowing the fusible link. Once the engine is started, the fusible link carries the current for all the car’s systems.


Concur w/TSM, it sounds like the electrical system is losing power for a brief time, then regaining it. Those dash lights come on at that point for the same reason that they come on when you turn the key from off to on, before you start the engine. Or when the engine stalls with the key in on.

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Thanks guys ! ! Would this have anything to do with a hard start condition as well? Truck has gotten to where it turns over good but acts like not getting spark.
And would the problem be there at the under hood box?

If you have no spark and your 1985 is like my 1979 (RIP), there’s a signal generator (AKA pickup coil) inside the distributor. It senses the turning of the shaft and tells the ignition system when to fire a spark. If it fails, you get weak or no spark.

There’s a very good chance that it does. If your ignition system can’t maintain a reliable spark, it can make the engine hard to start.
Fix the link problem and see. Post the results.

If you can figure out a way to temporarily install a dashboard volt meter (needle/dial type rather than numeric display if possible), you could watch what the battery voltage to the ignition system is doing when the problem occurs. If the needle is dropping or below 12 volts, you’d have a pretty good clue.

What size fusible link is this please?

Any parts store will be able to give you a direct replacement complete with connectors on the ends. Or it’s readily available on the internet from places like Autopartswarehouse and Carid.

My local Advance Auto Parts store didn’t have any replacement links. They did have a 10’ roll of fusible link wire which is about 9 and a half foot more than I needed.
And I’ve been told that it’s a 10 ga. 30 amp link.

If the source is reliable, go with it. If you’re not certain, I’m sure the dealer parts guy can tell you for certain.

Summit Racing’s website is often a good source for small lengths of fusible link.

Googling “fusible link wire” will show other sources