Smoked fusible link and ground wire

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70dartswing

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I'm looking for some help. I have a 70 Dart swinger 318 car. It sat for roughly 10 years. It supposedly ran when parked. I changed the intake, fuel tank, brakes all around, heater core and cleaned up some wiring. Today I went to start it for the first time. All the lights worked and the radio worked. When I turned the key it smoked the fusible link and and smoked a ground wire that was on a steering column bolt that ran to bottom of the steering column. I can not find anything grounding out anywhere. Thanks for the help!
 
Start at the amp meter, where the battery positive wire goes thru the firewall at the bulkhead connector, thru the meter, and the ignition switch. Many electrical problems start there. Mice may have gotten in there and eaten away the wire insulation, causing a direct short to ground.
 
70dartswing said:
I changed the intake, fuel tank, brakes all around, heater core and cleaned up some wiring.
Click to expand...
Specifically meaning what?
70dartswing said:
All the lights worked and the radio worked.
Click to expand...
Did the radio work with the ignition switch off, run or accessory?
70dartswing said:
When I turned the key it smoked the fusible link and and smoked a ground wire that was on a steering column bolt that ran to bottom of the steering column.
Click to expand...
Was this when you turned the key to Run or to Start?

The answer to which position the switch was will help you identify which circuit grounded out.

When a fusible link burns like that, it is because the battery found a direct path to ground.
On a stock '70 A-body the begining of that path would be as Gary mentioned.
It's the Battery feed/charge wiring to the main splice, and in your instance to the ignition switch. The grounding had to be a wire after the ignition switch .
Some simplified illustrations here.
Fusible Links in Charging Systems with Ammeter
 
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This is another simplified diagram showing why I'm asking about the switch position when it was OK and when it grounded out.
upload_2019-2-5_8-49-46.png

When you look at a factory diagram, the wires from the run position feeding the alternator field and ignition are labled ignition and have an identifier starting with J. The wire from the ignition switch to the fuse box is called accessory even though we may not think of those things that draw power from it as accessories. The accessory wire can also be powered alone from the accessory postion.
In Start a different set of wires gets power.
 
Mattax said:
Specifically meaning what?

Did the radio work with the ignition switch off, run or accessory?
Was this when you turned the key to Run or to Start?

The answer to which position the switch was will help you identify which circuit grounded out.

When a fusible link burns like that, it is because the battery found a direct path to ground.
On a stock '72 A-body the begining of that path would be as gary mentioned.
It's the Battery feed/charge wiring to the main splice, and in your instance to the ignition switch. The grounding had to be a wire after the ignition switch .
Some simplified illustrations here.
Fusible Links in Charging Systems with Ammeter
Click to expand...
The wiring was after market oil and coolant temp. Then some connectors under the hood that were loose or bare. The radio worked when the key was in the on position. Once turned to run it smoked both wires.
 
70dartswing said:
When I turn the key to the start position.
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OK. In Start power connection is made to the brown wire and yellow wire coming off the ignition switch in the diagram above.
Yellow represents the power to the trip the starter relay.
Brown represents Ignition 2, only used for starting. It connects to the coil side of the ballast resistor.

Above is a diagram to make it simpler to see how power flows.
Best to check the wiring diagram in a '70 Dodge or Plymouth Service Manual for the actual colors and connections.
 
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Well from your description a connection was made between the ignition switch Start position and ground. Only a couple of wires get power in Start so work from there.
Note which wires got smoked, which connection cavities show evidence of over heating, and you should should be able to figure out the path to ground.
Examples shown here:
Fusible Links in Charging Systems with Ammeter
 
Mattax said:
Well from your description a connection was made between the ignition switch Start position and ground. Only a couple of wires get power in Start so work from there.
I appreciate all your help
Note which wires got smoked, which connection cavities show evidence of over heating, and you should should be able to figure out the path to ground.
Examples shown here:
Fusible Links in Charging Systems with Ammeter
Click to expand...
 
Some comments here and there:

First if you do not have, go get/ download/ buy a factory service manual. You can download factory manuals as well as aftermarket wiring diagrams free from MyMopar

Next, look for melted harness wrappings. These girls are POORLY fused. In fact the "run" circuits and the "start" circuits ARE NOT FUSED except for the fusible link, and that is very poor protection. When things get hot, wires tend to melt the insulation and cross connect "weld" inside the harnesses

TO PROTECT THE SYSTEM WHILE TROUBLESHOOTING

Get yourself a BIG wattage 12V lamp. This can be an old headlamp, or even a stop/ turn socket with an 1157 bulb Wire the two 1157 wires together and connect to them at one terminal and the lamp shell for the other terminal

Install your "big lamp" in series with the battery ground cable. If you have a bad short, the bulb will light, alerting you, and it will LIMIT CURRENT FLOW protecting the entire system from further damage. Repair or temporarily repair the fuse link to get power back into the car

If the lamp lights,

1.....Make sure EVERYTHING in the car is off, including glove box/ courtesy and trunk lamps, the key, headlight switch, everything

2.....Pull fuses one at a time to see if the lamp goes dark

3....Unhook the main black wire from the alternator stud. "Safe" that wire off with tape temporarily.

4...If you can get the lamp "dark" then turn the key to "run." Lamp should light. Unhook alternator field (blue), unplug the VR, and pull connections off the ballast. Lamp might still glow but should not light brightly. If it does you have a short in that circuit

5.....Turn key to "start" after unhooking the two "push on" connectors on the starter relay. Lamp should not burn brightly, but will likely show some color. This is the current through the coil. You can disconnect the coil + wire temporarily. Lamp should go very dim or dark. If not the short is still in that circuit

Again, prepare to untape harnesses to inspect for damage. You may find yourself pulling the harnesses out, and no, that is no fun
 
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I wanted to add something when this happened my altenator was disconnected want the wires were taped up. Could it be part of the issues?
 
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