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It's the ignition switch harness. The factory soldered joints at the switch down to the connector is the portion that had the two wires melt. They're pretty big wires. This is on my LS swap, yes. I haven't done anything in this area though. It's a heavily wrapped and protected section of wires. I can't see how it could have shorted to ground. I'll investigate based on your idea of unfused power, thanks for the response.
Since the wires were only burnt between the switch and the first black connector is it safe to say the short to ground has to be between those two points? These wires in this ignition switch "harness" are the biggest wires in the circuit as far as I can tell. Does that tell me that the short has to be in that vicinity? In other words if the smaller wires in the circuit are fine can I assume the short is near or at these large wires? I'm frustrated because a few years ago with the old motor and Toyota harness, I had a meltdown of a bunch of wires in the engine bay, mainly the wires to the battery, and back to the big round yellow connector, and also some of the fuel injector wires. Back then I stripped everything off and ran new wires and it ran great until I retired it to do the swap. Now with this burn wire problem I'm wondering if there's some hidden gremlin somewhere.
No I'm not. I will check. Is your theory that it could be burnt somewhere else and that area might be a worn wire grounding out to metal? What's strange is that these ignition wires are the biggest wires in the whole circuit, except the big Alternator wires.
I think I might have found the source but not sure yet. I dissected the two burnt wires, they were IG2 and AM2. I covered them with electricians tape and re installed the switch and the truck started right up. I monitored everything closely and nothing got hot. I turned the truck off and did some other things and was going to go get some fuel. The truck would not start, same symptoms. So I checked the switch for voltage as I turned the key across the contacts and had nothing. So I removed it and got it on the bench and checked for continuity across all the contacts and everything is good there, but.... the contact I have pointing the red probe to (IGN2) and the black probe which is pointing to AM1, both are wiggle loose. I disassembled the switch and can't see a way to get to the contacts. Maybe internally theses made contact?
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- Are you actually going to mend this 10ga direct FULL ON battery voltage wires with electrical tape , re-install it and use it again after what occurred here ?
- i am going to guess say you have ...............humm........... over 177k on your FJ62 there ,.....a educated guess lets just say
- that's about the age , time , milage , and 9,999 stand alone rotary key switch , turns have occured before the internal copper contacts and steel check balls and springs turn into a Tom & Jerry Cartoon Clock exploding inside that round housing above ....
- mending wires here is not going to correct this internal mechanical and electrical clash of NEG- and POS+ voltage here that turned your 10ga wires into ashes in 4 seconds or less there
- these TOYOTA ignition key switches are NOT designed to take apart and repair inside ....fyi
- there is a safer , better way to go about this , that will not involve a TOYOTA TEq Fire Brigade FJ62 ?
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FJ62 3FE Ignition KEY Electrical Switch Fits 8/87-1990 Part # 84450-60150 / 88450-60151 3F-E - VintageTEqParts.com
- FJ62 3FE Ignition KEY Electrical Switch - Fits 8/87-1990 Part # 84450-60150 / 88450-60151 Date range Model...vintageteqparts.com
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i was not giving you grief , only making sure you understood , that it is a fire hazard at this point ...
i did not get the impression you planned on removing it after you patched it back together ?
that's all
Thanks Matt, what I ultimately discovered is that two of my original wires to the battery, with fusible links were loose. I fixed those and installed a new ignition switch. No issues since and no other wires were affected. I don't understand enough about this circuit to figure out why the wires from the ign. switch to the first black connector are the ones that got hot. Why my fusible links didn't go? Anyway, I thank everyone who tried to help.i was not giving you grief , only making sure you understood , that it is a fire hazard at this point ...
i did not get the impression you planned on removing it after you patched it back together ?
that's all
Hi Matt,- the internals on the round rotary switch are past there life cycle
- this WILL happen again , if it's not replaced ...
- fire under a dash on any TOYOTA is Scary thing
- this below , scares me more ,,, 1/79 FJ55LG-KA usa spec.
- this could be you if that old switch was re-used ...
thanks for the reply
matt
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Wow that's bad. Mine looks and feels solid.ONLY if after you remove the electrical key switch its super sloppy or binding ?
then YES
is normal smooth operation ?
then your SOLID !
make sense
or ?
is this going on below ...
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i would not show this , just fix it ..
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