Melted wires everywhere… need some help

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RecklessWOT

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Long story short, 86 stepside 5.0,
1976 350sbc installed by last owner...
Is it a 5.0 or a 350?

Generally saying "5.0" refers to the HO version of the furd 302 that was in the foxbody mustang (which ironically technically rounds to 4.9L by fractions of a ci). Obviously I know that's not what you meant (but it irks me when people say how many liters their old truck is, here in the US before the modern day with LS engines and such back in the day nobody knew what the hell a litre of displacement was, engines were measured in cubic inches). But even then in terms of small block Chevy engines, the 305 was 5 litres, a 350 is 5.7 litres in displacement. If you really have a 350 don't go around telling people you have a 5.0 or they're gonna think you got some lame ass 305 under the hood (no offense to anyone with a 305, but yeah come on you know it's weak lol). If you insist on stating its displacement in litres instead of cubic inches like an American, at least get it right and say 5.7L

Hah I'm also not actually trying to be a dick, this post was meant to be kinda joking around with the way I worded it. But for real, yeah a 350 is not 5.0L, it's 5.7L. Just sayin...
 

RecklessWOT

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Well I replaced numerous wires with proper gauge and tested the fuseable links and made sure my grounds/fuses were good. Still will not start. Test light shows power to the junction block, starter and hei (with key on).
I can turn the key to on and the battery gauge works until I try to start it then goes dead. I can also kill the battery gauge if I touch the headlight switch… not sure where to go from here.
On a more serious note, in response to your actual issue...

I know it seems simple, but how are your battery terminals? Are they loose? Corroded? Are the wires in good shape and tight where they connect to the terminals? I have had it happen on several occasions where there was enough contact for juice to flow and power the dome light/radio/etc, but as soon as you try to do something that draws a lot of power like the starter it's enough to break the connection completely and the thing acts as if it's got a stone cold dead battery until you go jiggle the battery cable. Then you hear the key buzzer kick back on and some relays clicking until you touch that key again.

Honestly it's not that far fetched unless you are SURE they're good. Commonly overlooked, especially on something that's been sitting around for a while. I've probably got 3 different vehicles in my driveway with such symptoms at the moment. Now that most likely wouldn't be what melted all your wires, but now that you've gone through all your grounds and fusible links and stuff and it's still acting this way, now it seems like there might have been multiple issues and this is just the last one left.

I hope you get it figured out soon. Man I hate electrical problems, I am horrible with that kind of stuff myself.
 

greene

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For sure a 350.
I’m puzzled too. New battery, new cables/calmps, added 2 extra grounds from the battery.
I’m going to pull the brand new starter tomorrow and have it tested.
 

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Turbo4whl

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Jason, Do you have, volt meter tool (multimeter)? Not the volt meter in the dash. You have a new battery, but if the alternator is not charging it, after a few starts the battery will be too low to start the engine again.

@RecklessWOT has a good point about loose connections. You replaced battery cables. Are the connections tight? What about the positive wire at the alternator, is it melted or loose?
 

AuroraGirl

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Well I replaced numerous wires with proper gauge and tested the fuseable links and made sure my grounds/fuses were good. Still will not start. Test light shows power to the junction block, starter and hei (with key on).
I can turn the key to on and the battery gauge works until I try to start it then goes dead. I can also kill the battery gauge if I touch the headlight switch… not sure where to go from here.
the battery voltmeter is not powered in crank is probably why
 

greene

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the battery voltmeter is not powered in crank is probably why
Very true, I wonder why it goes dead when I turn the headlight bezel also? I have power at the radio plug with key on also. Battery is over 13 Volts. And alternator positive tests good with a light but I could replace it if necessary.
 

AuroraGirl

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Very true, I wonder why it goes dead when I turn the headlight bezel also? I have power at the radio plug with key on also. Battery is over 13 Volts. And alternator positive tests good with a light but I could replace it if necessary.
what do you mean bezel? on the switch on the dash or you mean the one thats in front of the headlight for looks?
Very true, I wonder why it goes dead when I turn the headlight bezel also? I have power at the radio plug with key on also. Battery is over 13 Volts. And alternator positive tests good with a light but I could replace it if necessary.
Does your alternator test with a DVOM? A test light would tell you its got a connection to power.. the cable to the junction, which is wired to the battery. That isnt very helpful I wouldnt think. But if its the right voltage while running thats good.

Also on the alternator, some alternators Are good for the threaded post you wire the charge wire to to get loose. So theoretically the wire is tight but the post on the battery is loose so you could move them in unison. can you show pics of your battery and alt wiring
 

AuroraGirl

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Long story short, 86 stepside 5.0,
1976 350sbc installed by last owner with an accel distributor, man choke 1405, and a lot of melted wires. Need suggestions on what to do about the cut wires from the firewall (yellow arrow). I’m guessing it goes to the heater box that has badly melted wires. I can’t find any specific replacement harness for them. I’m guessing there isn’t one?
Pic 3 is an unused plug than I’m unsure of and pick 4 is also unplugged. What do these go to?
I ran the truck yesterday for about 20 minutes and shut it off. Half an hour later, I went to start it and it clicked once and then now it’s completely dead, no interior lights, headlights etc. with a key in the run position, the battery gauge will come on and show good voltage, but the second you try to start it, gauges shut down. I’m guessing it’s a fusible link? Do to the fact that I have a brand new battery and starter and ground wires. Should I try to make a new fusible link? Or I’m thinking about rewiring all the power wires/ crank wire all the way to the junction block. I plan on LS swapping in a few years but would hate to spend a lot of money on a painless harness that I won’t reuse.

And on the last pic, does anyones shock to frame mount look like a nine-year-old welded it?
What would you do about the cut wires and melted wires to the heater box? Thanks for the input.
Also, you have an 88-91 ish dipstick in your.. TH400? Not bad just an observation. Id wonder what your battery to engine ground is like at this time.
 

wlwarnke

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Are you getting power to the starter solenoid? Usually a purple wire. Becomes +12 while cranking.
 

greene

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I’m going to pull the purple crank wire tomorrow and see if it gets power with the ignition at the crank position.
What I was talking about with the gauges, I can turn the key to the run position and the volt gauge and fuel gauge come on and read correctly but as soon as I try anything electrical in the car like the headlights switch/dimmer or the cigarette lighter, all gauges go back to 0.
 

wlwarnke

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I’d check voltage at the battery and the junction block in the firewall. Other than the starter, everything else should be fed from the junction block
 

75gmck25

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If you test and find it works manually (you can jump the solenoid under the truck and it will turn over, etc.) except the key switch positions, it might be the ignition switch rack, or the actual electrical switch for the ignition.

There is nothing electrical on the end of the key switch in the column. The key switch just moves a small gear on the end, which moves a small toothed rack, which then pulls a rod going down the column. That rod moves the electrical switch that is mounted on the column above your feet. The switch can be out of adjustment at the lower end, or the rack mechanism can be broken.

If the ignition key switch rack is broken it will not move the electrical switch to the proper position to match the turning of the key. The rack is cheap, but requires a fair amount of column breakdown to replace.

This is the part you may need, but make sure you get the exact part number for your truck. https://www.amazon.com/dp/B000COBCL0/
Most Autozone used to stock these parts locally.
 

greene

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Well, found the problem. I started with replacing the the ignition switch on the steering column, and found a power wire that the previous owner used to power the radio. It was spliced together by the switch then ran to the radio. It was loose so I fixed it. Still nothing. Replaced the failing headlight switch. Nothing.

Then like half of everybody on this thread said, I cleaned the brand new battery terminals, posts and wires, sanded all the grounds down, and put them back. Of course it started it right up.
 

AuroraGirl

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Well, found the problem. I started with replacing the the ignition switch on the steering column, and found a power wire that the previous owner used to power the radio. It was spliced together by the switch then ran to the radio. It was loose so I fixed it. Still nothing. Replaced the failing headlight switch. Nothing.

Then like half of everybody on this thread said, I cleaned the brand new battery terminals, posts and wires, sanded all the grounds down, and put them back. Of course it started it right up.
GM side posts suck

If it was top post.. then if any connections were aluminum I blame aluminum oxide
 

Rusty Nail

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I’m unsure how long they have been like that, I got the truck about a month ago. Heater doesn’t work and there is no a/c compressor.
I’m going to start replacing wiring soon, I’ll probably use a painless kit.
I just wanted to drive it some before something major like that.
Bad azz cuz no history RULZ!
 

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