Short under the dash.

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75slant6

75slant6

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Ok guys, I THINK i have a short in the ignition wiring. When the key is in the run position, there’s no power, when it’s in the start position I have 12v to everything but it won’t crank, if I jump the starter the car will stay running when thekey is held in the start position. If I turn the key OFF something shorts and the connector under the dash starts smoking. As y’all can see, the connection of the pink wire got pretty hot.

So before I tear into it, I just wanted to get y’all’s opinion on what y’all think it is.

587EF1DB-60BC-4F53-851D-8D88E3E458BF.jpeg
 
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sounds like the ignition switch or direct switch wiring is shorted somewhere if you get smoke in OFF. start from the connector in hand, pull all fuses, disconnect battery, check for shorts to ground. disconnect everything you can reach, relays, regulator, ballast resistor, coil, firewall connectors, bulbs, etc...etc... get a meter and a wiring diagram from mymopar site. I just re-wired 2 barracudas and found multiple bad wires and connections in both with a meter. One major meltdown was the horn circuit, very odd. the other was the charging/starting circuits. (probably your problem)
 
75slant6 said:
If I turn the key OFF something shorts and the connector under the dash starts smoking. As y’all can see, the connection of the pink wire got pretty hot.
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Yes. It's shorting but hasn't blown the fusible link or any fuses. That narrows it already.

Get the wiring diagrams from the factory service manual (not the seperate diagram done by another company).
Write down where each wire and pin goes on the connector. Make a little diagram you can understand.
Disconnect the ign switch connector pictured. Use an ohm meter or continuity light, check both sides for continuity to ground on all suspect terminals.(Assuming the battery is disconnected by now). Then check for continuity to ground on the switch side. If neither turns up anything, try with switch on. Then start testing for cross-wire shorts.

Here's what you know already. It's not likely downstream of a fuse. So its probably before the fuse box, or on a circuit not protected by fuses (alternator field, ignition, maybe horn depending on year/model). But field and ignition should be off when the switch is off. If the short is across wires, that doesn't hold. But ckecking which wires are getting hot will narrow this down.

You also posted that it won't crank. If that means the starter doesn't energize, then it may involve the wire to the starter relay.
 
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One more hint. Its always worth glancing at the ammeter. It will indicate how much current is flowing to or from the battery.
I don't know the history of why many are labelled 'alternator'. That can be misleading. Sure was to me.
As you can see in the above diagrams,the ammeter is located between the battery and the main junction. So it only indicates how much current is flowing to or from the battery to the main junction. Probably won't be much help with this problem, but its worth knowing about.
 
Mattax said:
One more hint. Its always worth glancing at the ammeter. It will indicate how much current is flowing to or from the battery.
I don't know the history of why many are labelled 'alternator'. That can be misleading. Sure was to me.
As you can see in the above diagrams,the ammeter is located between the battery and the main junction. So it only indicates how much current is flowing to or from the battery to the main junction. Probably won't be much help with this problem, but its worth knowing about.
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I actually deleted the ammeter and replaced it with a volt meter
 
Unplug that connector, you have a bad connection causing a high resistance and causing low voltage high current at that connection and that will make a lot of heat. Run a wire from ammeter to fuseable link and don't use a connector. Then see if the problem goes away.
 
brian6pac said:
Unplug that connector, you have a bad connection causing a high resistance and causing low voltage high current at that connection and that will make a lot of heat. Run a wire from ammeter to fuseable link and don't use a connector. Then see if the problem goes away.
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Ammeter is bypassed as well as having the main power to/from the interior bypassing the bulkhead connector. Tbh, I don’t know if I even have a fusible link. I may have accidentally cut it out when I did the bulkhead bypass
 
75slant6 said:
Ammeter is bypassed as well as having the main power to/from the interior bypassing the bulkhead connector. Tbh, I don’t know if I even have a fusible link. I may have accidentally cut it out when I did the bulkhead bypass
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You need a fuse of some sort or you will be sorry when all the wires melt together,
maybe already happened! I would start pealing the rap off in places and look.
 
brian6pac said:
You need a fuse of some sort or you will be sorry when all the wires melt together,
maybe already happened! I would start pealing the rap off in places and look.
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Yea I need to see what size maxi fuse it’d take to put in there.
 
Go back to post three. That's still valid. Most of what's posted after that isn't, exept maybe Chryslers troubleshooting tips. I think you should make your own functional diagram, but that's your call. Everyone has different ways of understanding. For me, graphics are a big help.
 
75slant6 said:
Yea I need to see what size maxi fuse it’d take to put in there.
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Fuses and breakers should be sized based on the weakest wire or component downstream of the power source.
Most stuff is already protected by fuses and breakers. The ones to protect are the wires that are always hot - the ones attached to the battery with no switch or relay on them. If the alternator shorts, it shuts off; if the battery shorts to ground, its electrifying!
Fusible Links in Charging Systems with Ammeter
 
If you have a 30 amp meter your circuits are set up for 30 amps max but usually more for a short time, not for starter though. A fuse link will take more current for a longer time before it blows a maxi fuse is a fast blow fuse. You need to figure out what your current draw is when every thing is on to pick your maxi fuse or fuse link. Remember that your fuse link will be 1 gauge smaller than the wire that its connected to.
 
brian6pac said:
If you have a 30 amp meter your circuits are set up for 30 amps max but usually more for a short time, not for starter though. A fuse link will take more current for a longer time before it blows a maxi fuse is a fast blow fuse. You need to figure out what your current draw is when every thing is on to pick your maxi fuse or fuse link. Remember that your fuse link will be 1 gauge smaller than the wire that its connected to.
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So how would I see how much current everything is pulling to get the proper sized fusible link?
 
Hooked my multimeter to the melted wire in the switch connector and in the off position there’s definitely a short in the switch. Run and start positions show no irregularities. Got the column all torn apart, gonna repaint it while it’s apart then put in the ignition switch from a 72 Valiant parts car I have.
 
Mine looked exactly like that. I replaced the colume wiring and bam my stopping while driving did not happen anymore. You could cut the burnt looking wires and tie them together for a quick test and or fix.
 
Peter Bates said:
Mine looked exactly like that. I replaced the colume wiring and bam my stopping while driving did not happen anymore. You could cut the burnt looking wires and tie them together for a quick test and or fix.
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Column is currently in pieces, awaiting for me to have time to repaint it and swap in the wiring from my parts car.
 
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